Method of performing channel access procedure and apparatus therefor

ABSTRACT

Disclosed is a method of transmitting an uplink signal by a user equipment in a wireless communication system. Specifically, the method includes performing listen-before-talk (LBT) based on at least one LBT beam, and transmitting the uplink signal through a plurality of transmission beams based on success of the LBT. The at least one LBT beam covers the plurality of transmission beams, and the plurality of transmission beams is multiplexed.

TECHNICAL FIELD

The present disclosure relates to a method of performing a channelaccess procedure and an apparatus therefor and, more particularly, to amethod of performing a channel access procedure for transmitting andreceiving signals through multiplexed transmission beams, and anapparatus therefor.

BACKGROUND ART

As more and more communication devices demand larger communicationtraffic along with the current trends, a future-generation 5thgeneration (5G) system is required to provide an enhanced wirelessbroadband communication, compared to the legacy LTE system. In thefuture-generation 5G system, communication scenarios are divided intoenhanced mobile broadband (eMBB), ultra-reliability and low-latencycommunication (URLLC), massive machine-type communication (mMTC), and soon.

Herein, eMBB is a future-generation mobile communication scenariocharacterized by high spectral efficiency, high user experienced datarate, and high peak data rate, URLLC is a future-generation mobilecommunication scenario characterized by ultra-high reliability,ultra-low latency, and ultra-high availability (e.g., vehicle toeverything (V2X), emergency service, and remote control), and mMTC is afuture-generation mobile communication scenario characterized by lowcost, low energy, short packet, and massive connectivity (e.g., Internetof things (IoT)).

DISCLOSURE Technical Problem

An object of the present disclosure is to provide a method of performinga channel access procedure and an apparatus therefor.

It will be appreciated by persons skilled in the art that the objectsthat could be achieved with the present disclosure are not limited towhat has been particularly described hereinabove and the above and otherobjects that the present disclosure could achieve will be more clearlyunderstood from the following detailed description.

Technical Solution

According to an aspect of the present disclosure, provided herein is amethod of transmitting an uplink signal by a user equipment (UE) in awireless communication system, including performing listen-before-talk(LBT) based on at least one LBT beam, and transmitting the uplink signalthrough a plurality of transmission beams based on success of the LBT.The at least one LBT beam may cover the plurality of transmission beams,and the plurality of transmission beams may be multiplexed.

The plurality of transmission beams may be multiplexed using spatialdivision multiplexing (SDM).

The plurality of transmission beams may be multiplexed using timedivision multiplexing (TDM).

The at least one LBT beam may be a single LBT beam covering all of theplurality of transmission beams.

The at least one LBT beam may include a plurality of LBT beams, and eachof the plurality of LBT beams may cover each of the plurality oftransmission beams.

Category 2 (Cat-2) LBT may be performed before beam switching isperformed between the plurality of transmission beams.

In another aspect of the present disclosure, provided herein is a userequipment (UE) for transmitting an uplink signal in a wirelesscommunication system, including at least one transceiver; at least oneprocessor; and at least one memory operably connected to the at leastone processor and configured to store instructions causing, whenexecuted, the at least one processor to perform an operation. Theoperation may include performing listen-before-talk (LBT) based on atleast one LBT beam, and transmitting, through the at least onetransceiver, the uplink signal through a plurality of transmission beamsbased on success of the LBT. The at least one LBT beam may cover theplurality of transmission beams, and the plurality of transmission beamsmay be multiplexed.

The plurality of transmission beams may be multiplexed using spatialdivision multiplexing (SDM).

The plurality of transmission beams may be multiplexed using timedivision multiplexing (TDM).

The at least one LBT beam may be a single LBT beam covering all of theplurality of transmission beams.

The at least one LBT beam may include a plurality of LBT beams, and eachof the plurality of LBT beams may cover each of the plurality oftransmission beams.

Category 2 (Cat-2) LBT may be performed before beam switching isperformed between the plurality of transmission beams.

In another aspect of the present disclosure, provided herein is anapparatus for transmitting an uplink signal in a wireless communicationsystem, including at least one processor; and at least one memoryoperably connected to the at least one processor and configured to storeinstructions causing, when executed, the at least one processor toperform an operation. The operation may include performinglisten-before-talk (LBT) based on at least one LBT beam, andtransmitting the uplink signal through a plurality of transmission beamsbased on success of the LBT. The at least one LBT beam may cover theplurality of transmission beams, and the plurality of transmission beamsmay be multiplexed.

In another aspect of the present disclosure, provided herein is acomputer-readable storage medium including at least one computer programcausing at least one processor to perform an operation. The operationmay include performing listen-before-talk (LBT) based on at least oneLBT beam, and transmitting the uplink signal through a plurality oftransmission beams based on success of the LBT. The at least one LBTbeam may cover the plurality of transmission beams, and the plurality oftransmission beams may be multiplexed.

In another aspect of the present disclosure, provided herein is a methodof transmitting a downlink signal by a base station in a wirelesscommunication system, including performing listen-before-talk (LBT)based on at least one LBT beam, and transmitting the downlink signalthrough a plurality of transmission beams based on success of the LBT.The at least one LBT beam may cover the plurality of transmission beams,and the plurality of transmission beams may be multiplexed.

In another aspect of the present disclosure, provided herein is a basestation for transmitting a downlink signal in a wireless communicationsystem, including at least one transceiver; at least one processor; andat least one memory operably connected to the at least one processor andconfigured to store instructions causing, when executed, the at leastone processor to perform an operation. The operation may includeperforming listen-before-talk (LBT) based on at least one LBT beam, andtransmitting, through the at least one transceiver, the downlink signalthrough a plurality of transmission beams based on success of the LBT.The at least one LBT beam may cover the plurality of transmission beams,and the plurality of transmission beams may be multiplexed.

Advantageous Effects

According to the present disclosure, in order to overcome relativelylarge path loss occurring in a high-frequency band of 52.6 GHz orhigher, a BS and/or a UE may use directional listen-before-talk (D-LBT)and, when transmission beams in different directions are multiplexedwithin an obtained channel occupancy time (COT), a proper energydetection (ED) value, an LBT bandwidth, and/or an LBT beam for themultiplexed transmission beams may be configured.

It will be appreciated by persons skilled in the art that the effectsthat can be achieved with the present disclosure are not limited to whathas been particularly described hereinabove and other advantages of thepresent disclosure will be more clearly understood from the followingdetailed description taken in conjunction with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates physical channels and a general signal transmissionmethod using the physical channels in a 3rd generation partnershipproject (3GPP) system as an exemplary wireless communication system;

FIG. 2 illustrates a radio frame structure;

FIG. 3 illustrates a resource grid during the duration of a slot;

FIG. 4 illustrates exemplary mapping of physical channels in a slot;

FIG. 5 illustrates exemplary uplink (UL) transmission operations of auser equipment (UE);

FIG. 6 illustrates exemplary repeated transmissions based on aconfigured grant;

FIG. 7 illustrates a wireless communication system supporting anunlicensed band;

FIG. 8 illustrates an exemplary method of occupying resources in anunlicensed band;

FIG. 9 illustrates an exemplary channel access procedure of a UE for ULsignal transmission and/or DL signal transmission in an unlicensed bandapplicable to the present disclosure;

FIG. 10 is a diagram illustrating a plurality of listen-before-talksubbands (LBT-SBs) applicable to the present disclosure.

FIG. 11 is a diagram illustrating analog beamforming in the NR system;

FIGS. 12, 13, 14, 15, and 16 are diagrams illustrating beam managementin the NR system;

FIGS. 17 and 18 are diagrams illustrating a sounding reference signalapplicable to the present disclosure;

FIG. 19 is a diagram illustrating beam-based LBT and group-based LBTaccording to an embodiment of the present disclosure;

FIG. 20 is a diagram illustrating a problem occurring while beam-basedLBT is performed according to an embodiment of the present disclosure.

FIGS. 21 and 22 are diagrams illustrating overall operation processes ofa UE and a BS according to an embodiment of the present disclosure;

FIGS. 23, 24, and 25 are diagrams illustrating methods of performing LBTfor a plurality of multiplexed beams according to an embodiment of thepresent disclosure;

FIG. 26 illustrates an exemplary communication system applied to thepresent disclosure;

FIG. 27 illustrates an exemplary wireless device applicable to thepresent disclosure; and

FIG. 28 illustrates an exemplary vehicle or autonomous driving vehicleapplicable to the present disclosure.

BEST MODE

The following technology may be used in various wireless access systemssuch as code division multiple access (CDMA), frequency divisionmultiple access (FDMA), time division multiple access (TDMA), orthogonalfrequency division multiple access (OFDMA), single carrier frequencydivision multiple access (SC-FDMA), and so on. CDMA may be implementedas a radio technology such as universal terrestrial radio access (UTRA)or CDMA2000. TDMA may be implemented as a radio technology such asglobal system for mobile communications (GSM)/general packet radioservice (GPRS)/enhanced data rates for GSM evolution (EDGE). OFDMA maybe implemented as a radio technology such as institute of electrical andelectronics engineers (IEEE) 802.11 (wireless fidelity (Wi-Fi)), IEEE802.16 (worldwide interoperability for microwave access (WiMAX)), IEEE802.20, evolved UTRA (E-UTRA), and so on. UTRA is a part of universalmobile telecommunications system (UMTS). 3^(rd) generation partnershipproject (3GPP) long term evolution (LTE) is a part of evolved UMTS(E-UMTS) using E-UTRA, and LTE-advanced (LTE-A) is an evolution of 3GPPLTE. 3GPP new radio or new radio access technology (NR) is an evolvedversion of 3GPP LTE/LTE-A.

While the following description is given in the context of a 3GPPcommunication system (e.g., NR) for clarity, the technical spirit of thepresent disclosure is not limited to the 3GPP communication system. Forthe background art, terms, and abbreviations used in the presentdisclosure, refer to the technical specifications published before thepresent disclosure (e.g., 38.211, 38.212, 38.213, 38.214, 38.300,38.331, and so on).

5G communication involving a new radio access technology (NR) systemwill be described below.

Three key requirement areas of 5G are (1) enhanced mobile broadband(eMBB), (2) massive machine type communication (mMTC), and (3)ultra-reliable and low latency communications (URLLC).

Some use cases may require multiple dimensions for optimization, whileothers may focus only on one key performance indicator (KPI). 5Gsupports such diverse use cases in a flexible and reliable way.

eMBB goes far beyond basic mobile Internet access and covers richinteractive work, media and entertainment applications in the cloud oraugmented reality (AR). Data is one of the key drivers for 5G and in the5G era, we may for the first time see no dedicated voice service. In 5G,voice is expected to be handled as an application program, simply usingdata connectivity provided by a communication system. The main driversfor an increased traffic volume are the increase in the size of contentand the number of applications requiring high data rates. Streamingservices (audio and video), interactive video, and mobile Internetconnectivity will continue to be used more broadly as more devicesconnect to the Internet. Many of these applications require always-onconnectivity to push real time information and notifications to users.Cloud storage and applications are rapidly increasing for mobilecommunication platforms. This is applicable for both work andentertainment. Cloud storage is one particular use case driving thegrowth of uplink data rates. 5G will also be used for remote work in thecloud which, when done with tactile interfaces, requires much lowerend-to-end latencies in order to maintain a good user experience.Entertainment, for example, cloud gaming and video streaming, is anotherkey driver for the increasing need for mobile broadband capacity.Entertainment will be very essential on smart phones and tabletseverywhere, including high mobility environments such as trains, carsand airplanes. Another use case is AR for entertainment and informationsearch, which requires very low latencies and significant instant datavolumes.

One of the most expected 5G use cases is the functionality of activelyconnecting embedded sensors in every field, that is, mMTC. It isexpected that there will be 20.4 billion potential Internet of things(IoT) devices by 2020. In industrial IoT, 5G is one of areas that playkey roles in enabling smart city, asset tracking, smart utility,agriculture, and security infrastructure.

URLLC includes services which will transform industries withultra-reliable/available, low latency links such as remote control ofcritical infrastructure and self-driving vehicles. The level ofreliability and latency are vital to smart-grid control, industrialautomation, robotics, drone control and coordination, and so on.

Now, multiple use cases in a 5G communication system including the NRsystem will be described in detail.

5G may complement fiber-to-the home (FTTH) and cable-based broadband (ordata-over-cable service interface specifications (DOCSIS)) as a means ofproviding streams at data rates of hundreds of megabits per second togiga bits per second. Such a high speed is required for TV broadcasts ator above a resolution of 4K (6K, 8K, and higher) as well as virtualreality (VR) and AR. VR and AR applications mostly include immersivesport games. A special network configuration may be required for aspecific application program. For VR games, for example, game companiesmay have to integrate a core server with an edge network server of anetwork operator in order to minimize latency.

The automotive sector is expected to be a very important new driver for5G, with many use cases for mobile communications for vehicles. Forexample, entertainment for passengers requires simultaneous highcapacity and high mobility mobile broadband, because future users willexpect to continue their good quality connection independent of theirlocation and speed. Other use cases for the automotive sector are ARdashboards. These display overlay information on top of what a driver isseeing through the front window, identifying objects in the dark andtelling the driver about the distances and movements of the objects. Inthe future, wireless modules will enable communication between vehiclesthemselves, information exchange between vehicles and supportinginfrastructure and between vehicles and other connected devices (e.g.,those carried by pedestrians). Safety systems may guide drivers onalternative courses of action to allow them to drive more safely andlower the risks of accidents. The next stage will be remote-controlledor self-driving vehicles. These require very reliable, very fastcommunication between different self-driving vehicles and betweenvehicles and infrastructure. In the future, self-driving vehicles willexecute all driving activities, while drivers are focusing on trafficabnormality elusive to the vehicles themselves. The technicalrequirements for self-driving vehicles call for ultra-low latencies andultra-high reliability, increasing traffic safety to levels humanscannot achieve.

Smart cities and smart homes, often referred to as smart society, willbe embedded with dense wireless sensor networks. Distributed networks ofintelligent sensors will identify conditions for cost- andenergy-efficient maintenance of the city or home. A similar setup may bedone for each home, where temperature sensors, window and heatingcontrollers, burglar alarms, and home appliances are all connectedwirelessly. Many of these sensors are typically characterized by lowdata rate, low power, and low cost, but for example, real time highdefinition (HD) video may be required in some types of devices forsurveillance.

The consumption and distribution of energy, including heat or gas, isbecoming highly decentralized, creating the need for automated controlof a very distributed sensor network. A smart grid interconnects suchsensors, using digital information and communications technology togather and act on information. This information may include informationabout the behaviors of suppliers and consumers, allowing the smart gridto improve the efficiency, reliability, economics and sustainability ofthe production and distribution of fuels such as electricity in anautomated fashion. A smart grid may be seen as another sensor networkwith low delays.

The health sector has many applications that may benefit from mobilecommunications. Communications systems enable telemedicine, whichprovides clinical health care at a distance. It helps eliminate distancebarriers and may improve access to medical services that would often notbe consistently available in distant rural communities. It is also usedto save lives in critical care and emergency situations. Wireless sensornetworks based on mobile communication may provide remote monitoring andsensors for parameters such as heart rate and blood pressure.

Wireless and mobile communications are becoming increasingly importantfor industrial applications. Wires are expensive to install andmaintain, and the possibility of replacing cables with reconfigurablewireless links is a tempting opportunity for many industries. However,achieving this requires that the wireless connection works with asimilar delay, reliability and capacity as cables and that itsmanagement is simplified. Low delays and very low error probabilitiesare new requirements that need to be addressed with 5G.

Finally, logistics and freight tracking are important use cases formobile communications that enable the tracking of inventory and packageswherever they are by using location-based information systems. Thelogistics and freight tracking use cases typically require lower datarates but need wide coverage and reliable location information.

FIG. 1 illustrates physical channels and a general signal transmissionmethod using the physical channels in a 3GPP system.

When a UE is powered on or enters a new cell, the UE performs initialcell search (S11). The initial cell search involves acquisition ofsynchronization to a BS. For this purpose, the UE receives asynchronization signal block (SSB) from the BS. The SSB includes aprimary synchronization signal (PSS), a secondary synchronization signal(SSS), and a physical broadcast channel (PBCH). The UE synchronizes itstiming to the BS and acquires information such as a cell identifier (ID)based on the PSS/SSS. Further, the UE may acquire information broadcastin the cell by receiving the PBCH from the BS. During the initial cellsearch, the UE may also monitor a DL channel state by receiving adownlink reference signal (DL RS).

After the initial cell search, the UE may acquire more detailed systeminformation by receiving a physical downlink control channel (PDCCH) anda physical downlink shared channel (PDSCH) corresponding to the PDCCH(S12).

Subsequently, to complete connection to the BS, the UE may perform arandom access procedure with the BS (S13 to S16). Specifically, the UEmay transmit a preamble on a physical random access channel (PRACH)(S13) and may receive a PDCCH and a random access response (RAR) for thepreamble on a PDSCH corresponding to the PDCCH (S14). The UE may thentransmit a physical uplink shared channel (PUSCH) by using schedulinginformation in the RAR (S15), and perform a contention resolutionprocedure including reception of a PDCCH and a PDSCH signalcorresponding to the PDCCH (S16).

When the random access procedure is performed in two steps, steps S13and S15 may be performed as one step (in which Message A is transmittedby the UE), and steps S14 and S16 may be performed as one step (in whichMessage B is transmitted by the BS).

After the above procedure, the UE may receive a PDCCH and/or a PDSCHfrom the BS (S17) and transmit a physical uplink shared channel (PUSCH)and/or a physical uplink control channel (PUCCH) to the BS (S18), in ageneral UL/DL signal transmission procedure. Control information thatthe UE transmits to the BS is generically called uplink controlinformation (UCI). The UCI includes a hybrid automatic repeat andrequest acknowledgement/negative acknowledgement (HARQ-ACK/NACK), ascheduling request (SR), channel state information (CSI), and so on. TheCSI includes a channel quality indicator (CQI), a precoding matrix index(PMI), a rank indication (RI), and so on. In general, UCI is transmittedon a PUCCH. However, if control information and data should betransmitted simultaneously, the control information and the data may betransmitted on a PUSCH. In addition, the UE may transmit the UCIaperiodically on the PUSCH, upon receipt of a request/command from anetwork.

FIG. 2 illustrates a radio frame structure.

In NR, UL and DL transmissions are configured in frames. Each radioframe has a length of 10 ms and is divided into two 5-ms half-frames.Each half-frame is divided into five 1-ms subframes. A subframe isdivided into one or more slots, and the number of slots in a subframedepends on a subcarrier spacing (SCS). Each slot includes 12 or 14OFDM(A) symbols according to a cyclic prefix (CP). When a normal CP isused, each slot includes 14 OFDM symbols. When an extended CP is used,each slot includes 12 OFDM symbols. A symbol may include an OFDM symbol(or a CP-OFDM symbol) and an SC-FDMA symbol (or a discrete Fouriertransform-spread-OFDM (DFT-s-OFDM) symbol).

Table 1 exemplarily illustrates that the number of symbols per slot, thenumber of slots per frame, and the number of slots per subframe varyaccording to SCSs in a normal CP case.

TABLE 1 SCS (15*2{circumflex over ( )}u) N^(slot) _(symb) N^(frame, u)_(slot) N^(subframe, u) _(slot) 15 KHz (u = 0) 14 10 1 30 KHz (u = 1) 1420 2 60 KHz (u = 2) 14 40 4 120 KHz (u = 3)  14 80 8 240 KHz (u = 4)  14160 16 * N^(slot) _(symb): number of symbols in a slot * N^(frame, u)_(slot): number of slots in a frame * N^(subframe, u) _(slot): number ofslots in a subframe

Table 2 illustrates that the number of symbols per slot, the number ofslots per frame, and the number of slots per subframe vary according toSCSs in an extended CP case.

TABLE 2 SCS (15*2{circumflex over ( )}u) N^(slot) _(symb) N^(frame, u)_(slot) N^(subframe, u) _(slot) 60 KHz (u = 2) 12 40 4

The frame structure is merely an example, and the number of subframes,the number of slots, and the number of symbols in a frame may be changedin various manners. In the NR system, different OFDM(A) numerologies(e.g., SCSs, CP lengths, and so on) may be configured for a plurality ofcells aggregated for one UE. Accordingly, the (absolute time) durationof a time resource (e.g., a subframe, a slot, or a transmission timeinterval (TTI)) (for convenience, referred to as a time unit (TU))composed of the same number of symbols may be configured differentlybetween the aggregated cells.

In NR, various numerologies (or SCSs) may be supported to supportvarious 5^(th) generation (5G) services. For example, with an SCS of 15kHz, a wide area in traditional cellular bands may be supported, whilewith an SCS of 30 kHz or 60 kHz, a dense urban area, a lower latency,and a wide carrier bandwidth may be supported. With an SCS of 60 kHz orhigher, a bandwidth larger than 24.25 kHz may be supported to overcomephase noise.

An NR frequency band may be defined by two types of frequency ranges,FR1 and FR2. FR1 and FR2 may be configured as described in Table 3below. FR2 may be millimeter wave (mmW).

TABLE 3 Frequency Range Corresponding Subcarrier designation frequencyrange Spacing FR1  450 MHz-7125 MHz  15, 30, 60 kHz FR2 24250 MHz-52600MHz 60, 120, 240 kHz

FIG. 3 illustrates a resource grid during the duration of one slot. Aslot includes a plurality of symbols in the time domain. For example,one slot includes 14 symbols in a normal CP case and 12 symbols in anextended CP case. A carrier includes a plurality of subcarriers in thefrequency domain. A resource block (RB) may be defined by a plurality of(e.g., 12) consecutive subcarriers in the frequency domain. A bandwidthpart (BWP) may be defined by a plurality of consecutive (physical) RBs((P)RBs) in the frequency domain and correspond to one numerology (e.g.,SCS, CP length, and so on). A carrier may include up to N (e.g., 5)BWPs. Data communication may be conducted in an active BWP, and only oneBWP may be activated for one UE. Each element in a resource grid may bereferred to as a resource element (RE), to which one complex symbol maybe mapped.

FIG. 4 illustrates exemplary mapping of physical channels in a slot.

A DL control channel, DL or UL data, and a UL control channel may all beincluded in one slot. For example, the first N symbols (hereinafter,referred to as a DL control region) in a slot may be used to transmit aDL control channel, and the last M symbols (hereinafter, referred to asa UL control region) in the slot may be used to transmit a UL controlchannel. N and M are integers equal to or greater than 0. A resourceregion (hereinafter, referred to as a data region) between the DLcontrol region and the UL control region may be used for DL datatransmission or UL data transmission. A time gap for DL-to-UL orUL-to-DL switching may be defined between a control region and the dataregion. A PDCCH may be transmitted in the DL control region, and a PDSCHmay be transmitted in the DL data region. Some symbols at the time ofswitching from DL to UL in a slot may be configured as the time gap.

Now, a detailed description will be given of physical channels.

DL Channel Structures

An eNB transmits related signals on later-described DL channels to a UE,and the UE receives the related signals on the DL channels from the eNB.

(1) Physical Downlink Shared Channel (PDSCH)

The PDSCH carries DL data (e.g., a DL-shared channel transport block(DL-SCH TB)) and adopts a modulation scheme such as quadrature phaseshift keying (QPSK), 16-ary quadrature amplitude modulation (16 QAM),64-ary QAM (64 QAM), or 256-ary QAM (256 QAM). A TB is encoded to acodeword. The PDSCH may deliver up to two codewords. The codewords areindividually subjected to scrambling and modulation mapping, andmodulation symbols from each codeword are mapped to one or more layers.An OFDM signal is generated by mapping each layer together with a DMRSto resources, and transmitted through a corresponding antenna port.

(2) Physical Downlink Control Channel (PDCCH)

The PDCCH delivers DCI. For example, the PDCCH (i.e., DCI) may carryinformation about a transport format and resource allocation of a DLshared channel (DL-SCH), resource allocation information of an uplinkshared channel (UL-SCH), paging information on a paging channel (PCH),system information on the DL-SCH, information on resource allocation ofa higher-layer control message such as an RAR transmitted on a PDSCH, atransmit power control command, information about activation/release ofconfigured scheduling, and so on. The DCI includes a cyclic redundancycheck (CRC). The CRC is masked with various identifiers (IDs) (e.g. aradio network temporary identifier (RNTI)) according to an owner orusage of the PDCCH. For example, if the PDCCH is for a specific UE, theCRC is masked by a UE ID (e.g., cell-RNTI (C-RNTI)). If the PDCCH is fora paging message, the CRC is masked by a paging-RNTI (P-RNTI). If thePDCCH is for system information (e.g., a system information block(SIB)), the CRC is masked by a system information RNTI (SI-RNTI). Whenthe PDCCH is for an RAR, the CRC is masked by a random access-RNTI(RA-RNTI).

The PDCCH uses a fixed modulation scheme (e.g., QPSK). One PDCCHincludes 1, 2, 4, 8, or 16 control channel elements (CCEs) according toits aggregation level (AL). One CCE includes 6 resource element groups(REGs), each REG being defined by one OFDM symbol by one (P)RB.

The PDCCH is transmitted in a control resource set (CORESET). TheCORESET corresponds to a set of physical resources/parameters used todeliver the PDCCH/DCI in a BWP. For example, the CORESET is defined as aset of REGs with a given numerology (e.g., an SCS, a CP length, or thelike). The CORESET may be configured by system information (e.g., amaster information block (MIB)) or UE-specific higher-layer signaling(e.g., RRC signaling). For example, the following parameters/informationmay be used to configure a CORESET, and a plurality of CORESETs mayoverlap with each other in the time/frequency domain.

-   -   controlResourceSetId: indicates the ID of a CORESET.    -   frequencyDomainResources: indicates the frequency area resources        of the CORESET. The frequency area resources are indicated by a        bitmap, and each bit of the bitmap corresponds to an RB group        (i.e., six consecutive RBs). For example, the most significant        bit (MSB) of the bitmap corresponds to the first RB group of a        BWP. An RB group corresponding to a bit set to 1 is allocated as        frequency area resources of the CORESET.    -   duration: indicates the time area resources of the CORESET. It        indicates the number of consecutive OFDMA symbols in the        CORESET. For example, the duration is set to one of 1 to 3.    -   cce-REG-MappingType: indicates a CCE-to-REG mapping type. An        interleaved type and a non-interleaved type are supported.    -   precoderGranularity: indicates a precoder granularity in the        frequency domain.    -   tci-StatesPDCCH: provides information indicating a transmission        configuration indication (TCI) state for the PDCCH (e.g.,        TCI-StateID). The TCI state is used to provide the        quasi-co-location relation between DL RS(s) in an RS set        (TCI-state) and PDCCH DMRS ports.    -   tci-PresentInDCI: indicates whether a TCI field is included in        DCI.    -   pdcch-DMRS-ScramblingID: provides information used for        initialization of a PDCCH DMRS scrambling sequence.

To receive the PDCCH, the UE may monitor (e.g., blind-decode) a set ofPDCCH candidates in the CORESET. The PDCCH candidates are CCE(s) thatthe UE monitors for PDCCH reception/detection. The PDCCH monitoring maybe performed in one or more CORESETs in an active DL BWP on each activecell configured with PDCCH monitoring. A set of PDCCH candidatesmonitored by the UE is defined as a PDCCH search space (SS) set. The SSset may be a common search space (CSS) set or a UE-specific search space(USS) set.

Table 4 lists exemplary PDCCH SSs.

TABLE 4 Search Type Space RNTI Use Case Type0- Common SI-RNTI on aprimary cell SIB Decoding PDCCH Type0A- Common SI-RNTI on a primary cellSIB Decoding PDCCH Type1- Common RA-RNTI or TC-RNTI on a Msg2, Msg4PDCCH primary cell decoding in RACH Type2- Common P-RNTI on a primarycell Paging PDCCH Decoding Type3- Common INT-RNTI, SFI-RNTI, TPC- PDCCHPUSCH-RNTI, TPC-PUCCH- RNTI, TPC-SRS-RNTI, C- RNTI, MCS-C-RNTI, or CS-RNTI(s) UE Specific UE C-RNTI, or MCS-C-RNTI, or User specific SpecificCS-RNTI(s) PDSCH decoding

The SS set may be configured by system information (e.g., MIB) orUE-specific higher-layer (e.g., RRC) signaling. S or fewer SS sets maybe configured in each DL BWP of a serving cell. For example, thefollowing parameters/information may be provided for each SS set. EachSS set may be associated with one CORESET, and each CORESETconfiguration may be associated with one or more SS sets.—searchSpaceId: indicates the ID of the SS set.

-   -   controlResourceSetId: indicates a CORESET associated with the SS        set.    -   monitoringSlotPeriodicityAndOffset: indicates a PDCCH monitoring        periodicity (in slots) and a PDCCH monitoring offset (in slots).    -   monitoringSymbolsWithinSlot: indicates the first OFDMA symbol(s)        for PDCCH monitoring in a slot configured with PDCCH monitoring.        The OFDMA symbols are indicated by a bitmap and each bit of the        bitmap corresponds to one OFDM symbol in the slot. The MSB of        the bitmap corresponds to the first OFDM symbol of the slot.        OFDMA symbol(s) corresponding to bit(s) set to 1 corresponds to        the first symbol(s) of the CORESET in the slot.    -   nrofCandidates: indicates the number of PDCCH candidates (e.g.,        one of 0, 1, 2, 3, 4, 5, 6, and 8) for each AL={1, 2, 4, 8, 16}.    -   searchSpaceType: indicates whether the SS type is CSS or USS.    -   DCI format: indicates the DCI format of PDCCH candidates.

The UE may monitor PDCCH candidates in one or more SS sets in a slotbased on a CORESET/SS set configuration. An occasion (e.g.,time/frequency resources) in which the PDCCH candidates should bemonitored is defined as a PDCCH (monitoring) occasion. One or more PDCCH(monitoring) occasions may be configured in a slot.

Table 5 illustrates exemplary DCI formats transmitted on the PDCCH.

TABLE 5 DCI format Usage 0_0 Scheduling of PUSCH in one cell 0_1Scheduling of PUSCH in one cell 1_0 Scheduling of PDSCH in one cell 1_1Scheduling of PDSCH in one cell 2_0 Notifying a group of UEs of the slotformat 2_1 Notifying a group of UEs of the PRB(s) and OFDM symbol(s)where UE may assume no transmission is intended for the UE 2_2Transmission of TPC commands for PUCCH and PUSCH 2_3 Transmission of agroup of TPC commands for SRS transmissions by one or more UEs

DCI format 0_0 may be used to schedule a TB-based (or TB-level) PUSCH,and DCI format 0_1 may be used to schedule a TB-based (or TB-level)PUSCH or a code block group (CBG)-based (or CBG-level) PUSCH. DCI format1_0 may be used to schedule a TB-based (or TB-level) PDSCH, and DCIformat 1_1 may be used to schedule a TB-based (or TB-level) PDSCH or aCBG-based (or CBG-level) PDSCH (DL grant DCI). DCI format 0_0/0_1 may bereferred to as UL grant DCI or UL scheduling information, and DCI format1_0/1_1 may be referred to as DL grant DCI or DL scheduling information.DCI format 2_0 is used to deliver dynamic slot format information (e.g.,a dynamic slot format indicator (SFI)) to a UE, and DCI format 2_1 isused to deliver DL pre-emption information to a UE. DCI format 2_0and/or DCI format 2_1 may be delivered to a corresponding group of UEson a group common PDCCH which is a PDCCH directed to a group of UEs. DCIformat 0_0 and DCI format 1_0 may be referred to as fallback DCIformats, whereas DCI format 0_1 and DCI format 1_1 may be referred to asnon-fallback DCI formats. In the fallback DCI formats, a DCI size/fieldconfiguration is maintained to be the same irrespective of a UEconfiguration. In contrast, the DCI size/field configuration variesdepending on a UE configuration in the non-fallback DCI formats.

UL Channel Structures

A UE transmits a related signal to the BS on a UL channel, which will bedescribed later, and the BS receives the related signal from the UEthrough the UL channel to be described later.

(1) Physical Uplink Control Channel (PUCCH)

The PUCCH carries UCI, HARQ-ACK and/or scheduling request (SR), and isdivided into a short PUCCH and a long PUCCH according to the PUCCHtransmission length.

The UCI includes the following information.

-   -   SR: information used to request UL-SCH resources.    -   HARQ-ACK: a response to a DL data packet (e.g., codeword) on the        PDSCH. An HARQ-ACK indicates whether the DL data packet has been        successfully received. In response to a single codeword, a 1-bit        of HARQ-ACK may be transmitted. In response to two codewords, a        2-bit HARQ-ACK may be transmitted. The HARQ-ACK response        includes positive ACK (simply, ACK), negative ACK (NACK),        discontinuous transmission (DTX) or NACK/DTX. The term HARQ-ACK        is interchangeably used with HARQ ACK/NACK and ACK/NACK.    -   CSI: feedback information for a DL channel. Multiple input        multiple output (MIMO)-related feedback information includes an        RI and a PMI.

Table 6 illustrates exemplary PUCCH formats. PUCCH formats may bedivided into short PUCCHs (Formats 0 and 2) and long PUCCHs (Formats 1,3, and 4) based on PUCCH transmission durations.

TABLE 6 Length in OFDM PUCCH symbols Number format N_(symb) ^(PUCCH) ofbits Usage Etc 0 1-2  ≤2 HARQ, SR Sequence selection 1 4-14 ≤2 HARQ,Sequence modulation [SR] 2 1-2  >2 HARQ, CP-OFDM CSI, [SR] 3 4-14 >2HARQ, DFT-s-OFDM CSI, [SR] (no UE multiplexing) 4 4-14 >2 HARQ,DFT-s-OFDM CSI, [SR] (Pre DFT OCC)

PUCCH format 0 conveys UCI of up to 2 bits and is mapped in asequence-based manner, for transmission. Specifically, the UE transmitsspecific UCI to the BS by transmitting one of a plurality of sequenceson a PUCCH of PUCCH format 0. Only when the UE transmits a positive SR,the UE transmits the PUCCH of PUCCH format 0 in PUCCH resources for acorresponding SR configuration. PUCCH format 1 conveys UCI of up to 2bits and modulation symbols of the UCI are spread with an orthogonalcover code (OCC) (which is configured differently whether frequencyhopping is performed) in the time domain. The DMRS is transmitted in asymbol in which a modulation symbol is not transmitted (i.e.,transmitted in time division multiplexing (TDM)).

PUCCH format 2 conveys UCI of more than 2 bits and modulation symbols ofthe DCI are transmitted in frequency division multiplexing (FDM) withthe DMRS. The DMRS is located in symbols #1, #4, #7, and #10 of a givenRB with a density of ⅓. A pseudo noise (PN) sequence is used for a DMRSsequence. For 2-symbol PUCCH format 2, frequency hopping may beactivated.

PUCCH format 3 does not support UE multiplexing in the same PRBs, andconveys UCI of more than 2 bits. In other words, PUCCH resources ofPUCCH format 3 do not include an OCC. Modulation symbols are transmittedin TDM with the DMRS.

PUCCH format 4 supports multiplexing of up to 4 UEs in the same PRBS,and conveys UCI of more than 2 bits. In other words, PUCCH resources ofPUCCH format 3 include an OCC. Modulation symbols are transmitted in TDMwith the DMRS.

(2) Physical Uplink Shared Channel (PUSCH)

The PUSCH carries UL data (e.g., UL-shared channel transport block(UL-SCH TB)) and/or UL control information (UCI), and is transmittedbased a Cyclic Prefix-Orthogonal Frequency Division Multiplexing(CP-OFDM) waveform or a Discrete Fourier Transform-spread-OrthogonalFrequency Division Multiplexing (DFT-s-OFDM) waveform. When the PUSCH istransmitted based on the DFT-s-OFDM waveform, the UE transmits the PUSCHby applying transform precoding. For example, when transform precodingis not allowed (e.g., transform precoding is disabled), the UE maytransmit the PUSCH based on the CP-OFDM waveform. When transformprecoding is allowed (e.g., transform precoding is enabled), the UE maytransmit the PUSCH based on the CP-OFDM waveform or the DFT-s-OFDMwaveform. PUSCH transmission may be dynamically scheduled by the ULgrant in the DCI or may be semi-statically scheduled based on higherlayer (e.g., RRC) signaling (and/or Layer 1 (L1) signaling (e.g.,PDCCH)) (configured grant). PUSCH transmission may be performed on acodebook basis or a non-codebook basis.

On DL, the BS may dynamically allocate resources for DL transmission tothe UE by PDCCH(s) (including DCI format 1_0 or DCI format 1_1).Further, the BS may indicate to a specific UE that some of resourcespre-scheduled for the UE have been pre-empted for signal transmission toanother UE, by PDCCH(s) (including DCI format 2_1). Further, the BS mayconfigure a DL assignment periodicity by higher-layer signaling andsignal activation/deactivation of a configured DL assignment by a PDCCHin a semi-persistent scheduling (SPS) scheme, to provide a DL assignmentfor an initial HARQ transmission to the UE. When a retransmission forthe initial HARQ transmission is required, the BS explicitly schedulesretransmission resources through a PDCCH. When a DCI-based DL assignmentcollides with an SPS-based DL assignment, the UE may give priority tothe DCI-based DL assignment.

Similarly to DL, for UL, the BS may dynamically allocate resources forUL transmission to the UE by PDCCH(s) (including DCI format 0_0 or DCIformat 0_1). Further, the BS may allocate UL resources for initial HARQtransmission to the UE based on a configured grant (CG) method(similarly to SPS). Although dynamic scheduling involves a PDCCH for aPUSCH transmission, a configured grant does not involve a PDCCH for aPUSCH transmission. However, UL resources for retransmission areexplicitly allocated by PDCCH(s). As such, an operation ofpreconfiguring UL resources without a dynamic grant (DG) (e.g., a ULgrant through scheduling DCI) by the BS is referred to as a “CG”. Twotypes are defined for the CG.

-   -   Type 1: a UL grant with a predetermined periodicity is provided        by higher-layer signaling (without L1 signaling).    -   Type 2: the periodicity of a UL grant is configured by        higher-layer signaling, and activation/deactivation of the CG is        signaled by a PDCCH, to provide the UL grant.

FIG. 5 illustrates exemplary UL transmission operations of a UE. The UEmay transmit an intended packet based on a DG (FIG. 5(a)) or based on aCG (FIG. 5(b)).

Resources for CGs may be shared between a plurality of UEs. A UL signaltransmission based on a CG from each UE may be identified bytime/frequency resources and an RS parameter (e.g., a different cyclicshift or the like). Therefore, when a UE fails in transmitting a ULsignal due to signal collision, the BS may identify the UE andexplicitly transmit a retransmission grant for a corresponding TB to theUE.

K repeated transmissions including an initial transmission are supportedfor the same TB by a CG. The same HARQ process ID is determined for Ktimes repeated UL signals based on resources for the initialtransmission. The redundancy versions (RVs) of a K times repeated TBhave one of the patterns {0, 2, 3, 1}, {0, 3, 0, 3}, and {0, 0, 0, 0}.

FIG. 6 illustrates exemplary repeated transmissions based on a CG.

The UE performs repeated transmissions until one of the followingconditions is satisfied:

-   -   A UL grant for the same TB is successfully received;    -   The repetition number of the TB reaches K; and    -   (In Option 2) the ending time of a period P is reached.

Similarly to licensed-assisted access (LAA) in the legacy 3GPP LTEsystem, use of an unlicensed band for cellular communication is alsounder consideration in a 3GPP NR system. Unlike LAA, a stand-along (SA)operation is aimed in an NR cell of an unlicensed band (hereinafter,referred to as NR unlicensed cell (UCell)). For example, PUCCH, PUSCH,and PRACH transmissions may be supported in the NR UCell.

On LAA UL, with the introduction of an asynchronous HARQ procedure,there is no additional channel such as a physical HARQ indicator channel(PHICH) for indicating HARQ-ACK information for a PUSCH to the UE.Therefore, accurate HARQ-ACK information may not be used to adjust acontention window (CW) size in a UL LBT procedure. In the UL LBTprocedure, when a UL grant is received in the n-th subframe, the firstsubframe of the most recent UL transmission burst prior to the (n−3)-thsubframe has been configured as a reference subframe, and the CW sizehas been adjusted based on a new data indicator (NDI) for a HARQ processID corresponding to the reference subframe. That is, when the BS togglesNDIs per one or more transport blocks (TBs) or instructs that one ormore TBs be retransmitted, a method has been introduced of increasingthe CW size to the next largest CW size of a currently applied CW sizein a set for pre-agreed CW sizes under the assumption that transmissionof a PUSCH has failed in the reference subframe due to collision withother signals or initializing the CW size to a minimum value (e.g.,CWmin) under the assumption that the PUSCH in the reference subframe hasbeen successfully transmitted without any collision with other signals.

In an NR system to which various embodiments of the present disclosureare applicable, up to 400 MHz per component carrier (CC) may beallocated/supported. When a UE operating in such a wideband CC alwaysoperates with a radio frequency (RF) module turned on for the entire CC,battery consumption of the UE may increase.

Alternatively, considering various use cases (e.g., eMBB, URLLC, mMTC,and so on) operating within a single wideband CC, a different numerology(e.g., SCS) may be supported for each frequency band within the CC.

Alternatively, each UE may have a different maximum bandwidthcapability.

In this regard, the BS may indicate to the UE to operate only in apartial bandwidth instead of the total bandwidth of the wideband CC. Thepartial bandwidth may be defined as a bandwidth part (BWP).

A BWP may be a subset of contiguous RBs on the frequency axis. One BWPmay correspond to one numerology (e.g., SCS, CP length, slot/mini-slotduration, and so on).

The BS may configure multiple BWPs in one CC configured for the UE. Forexample, the BS may configure a BWP occupying a relatively smallfrequency area in a PDCCH monitoring slot, and schedule a PDSCHindicated (or scheduled) by a PDCCH in a larger BWP. Alternatively, whenUEs are concentrated on a specific BWP, the BS may configure another BWPfor some of the UEs, for load balancing. Alternatively, the BS mayexclude some spectrum of the total bandwidth and configure both-sideBWPs of the cell in the same slot in consideration of frequency-domaininter-cell interference cancellation between neighboring cells.

The BS may configure at least one DL/UL BWP for a UE associated with thewideband CC, activate at least one of DL/UL BWP(s) configured at aspecific time point (by L1 signaling (e.g., DCI), MAC signaling, or RRCsignaling), and indicate switching to another configured DL/UL BWP (byL1 signaling, MAC signaling, or RRC signaling). Further, upon expirationof a timer value (e.g., a BWP inactivity timer value), the UE may switchto a predetermined DL/UL BWP. The activated DL/UL BWP may be referred toas an active DL/UL BWP. During initial access or before an RRCconnection setup, the UE may not receive a configuration for a DL/UL BWPfrom the BS. A DL/UL BWP that the UE assumes in this situation isdefined as an initial active DL/UL BWP.

FIG. 7 illustrates an exemplary wireless communication system supportingan unlicensed band applicable to the present disclosure.

In the following description, a cell operating in a licensed band(L-band) is defined as an L-cell, and a carrier of the L-cell is definedas a (DL/UL) LCC. A cell operating in an unlicensed band (U-band) isdefined as a U-cell, and a carrier of the U-cell is defined as a (DL/UL)UCC. The carrier/carrier-frequency of a cell may refer to the operatingfrequency (e.g., center frequency) of the cell. A cell/carrier (e.g.,CC) is commonly called a cell.

When a BS and a UE transmit and receive signals on carrier-aggregatedLCC and UCC as illustrated in FIG. 7(a), the LCC and the UCC may beconfigured as a primary CC (PCC) and a secondary CC (SCC), respectively.The BS and the UE may transmit and receive signals on one UCC or on aplurality of carrier-aggregated UCCs as illustrated in FIG. 7(b). Inother words, the BS and UE may transmit and receive signals only onUCC(s) without using any LCC. For an SA operation, PRACH, PUCCH, PUSCH,and SRS transmissions may be supported on a UCell.

Signal transmission and reception operations in an unlicensed band asdescribed in the present disclosure may be applied to theafore-mentioned deployment scenarios (unless specified otherwise).

Unless otherwise noted, the definitions below are applicable to thefollowing terminologies used in the present disclosure.

-   -   Channel: a carrier or a part of a carrier composed of a        contiguous set of RBs in which a channel access procedure (CAP)        is performed in a shared spectrum.    -   Channel access procedure (CAP): a procedure of assessing channel        availability based on sensing before signal transmission in        order to determine whether other communication node(s) are using        a channel. A basic sensing unit is a sensing slot with a        duration of T_(sl)=9 us. The BS or the UE senses the slot during        a sensing slot duration. When power detected for at least 4 us        within the sensing slot duration is less than an energy        detection threshold X_(thresh), the sensing slot duration T_(sl)        is be considered to be idle. Otherwise, the sensing slot        duration T_(sl) is considered to be busy. CAP may also be called        listen before talk (LBT).    -   Channel occupancy: transmission(s) on channel(s) from the BS/UE        after a CAP.    -   Channel occupancy time (COT): a total time during which the        BS/UE and any BS/UE(s) sharing channel occupancy performs        transmission(s) on a channel after a CAP. Regarding COT        determination, if a transmission gap is less than or equal to 25        us, the gap duration may be counted in a COT.

The COT may be shared for transmission between the BS and correspondingUE(s).

Specifically, sharing a UE-initiated COT with the BS may mean anoperation in which the UE assigns a part of occupied channels throughrandom backoff-based LBT (e.g., Category 3 (Cat-3) LBT or Category 4(Cat-4) LBT) to the BS and the BS performs DL transmission using aremaining COT of the UE, when it is confirmed that a channel is idle bysuccess of LBT after performing LBT without random backoff (e.g.,Category 1 (Cat-1) LBT or Category 2 (Cat-2) LBT) using a timing gapoccurring before DL transmission start from a UL transmission end timingof the UE.

Meanwhile, sharing a gNB-initiated COT with the UE may mean an operationin which the BS assigns a part of occupied channels through randombackoff-based LBT (e.g., Cat-3 LBT or Cat-4 LBT) to the UE and the UEperforms UL transmission using a remaining COT of the BS, when it isconfirmed that a channel is idle by success of LBT after performing LBTwithout random backoff (e.g., Cat-1 LBT or Cat-2 LBT) using a timing gapoccurring before UL transmission start from a DL transmission end timingof the BS.

-   -   DL transmission burst: a set of transmissions without any gap        greater than 16 us from the BS. Transmissions from the BS, which        are separated by a gap exceeding 16 us are considered as        separate DL transmission bursts. The BS may perform        transmission(s) after a gap without sensing channel availability        within a DL transmission burst.    -   UL transmission burst: a set of transmissions without any gap        greater than 16 us from the UE. Transmissions from the UE, which        are separated by a gap exceeding 16 us are considered as        separate UL transmission bursts. The UE may perform        transmission(s) after a gap without sensing channel availability        within a DL transmission burst.    -   Discovery burst: a DL transmission burst including a set of        signal(s) and/or channel(s) confined within a window and        associated with a duty cycle. The discovery burst may include        transmission(s) initiated by the BS, which includes a PSS, an        SSS, and a cell-specific RS (CRS) and further includes a        non-zero power CSI-RS. In the NR system, the discover burst        includes may include transmission(s) initiated by the BS, which        includes at least an SS/PBCH block and further includes a        CORESET for a PDCCH scheduling a PDSCH carrying SIB1, the PDSCH        carrying SIB1, and/or a non-zero power CSI-RS.

FIG. 8 illustrates an exemplary method of occupying resources in anunlicensed band.

Referring to FIG. 8 , a communication node (e.g., a BS or a UE)operating in an unlicensed band should determine whether othercommunication node(s) is using a channel, before signal transmission.For this purpose, the communication node may perform a CAP to accesschannel(s) on which transmission(s) is to be performed in the unlicensedband. The CAP may be performed based on sensing. For example, thecommunication node may determine whether other communication node(s) istransmitting a signal on the channel(s) by carrier sensing (CS) beforesignal transmission. Determining that other communication node(s) is nottransmitting a signal is defined as confirmation of clear channelassessment (CCA). In the presence of a CCA threshold (e.g., X_(thresh))which has been predefined or configured by higher-layer (e.g., RRC)signaling, the communication node may determine that the channel isbusy, when detecting energy higher than the CCA threshold in thechannel. Otherwise, the communication node may determine that thechannel is idle. When determining that the channel is idle, thecommunication node may start to transmit a signal in the unlicensedband. CAP may be replaced with LBT.

Table 7 describes an exemplary CAP supported in NR-U.

TABLE 7 Type Explanation DL Type 1 CAP CAP with random back-off timeduration spanned by the sensing slots that are sensed to be idle beforea downlink transmission(s) is random Type 2 CAP CAP without randomback-off Type 2A, time duration spanned by sensing slots 2B, 2C that aresensed to be idle before a down- link transmission(s) is deterministicUL Type 1 CAP CAP with random back-off time duration spanned by thesensing slots that are sensed to be idle before a down- linktransmission(s) is random Type 2 CAP CAP without random back-off Type2A, time duration spanned by sensing slots 2B, 2C that are sensed to beidle before a down- link transmission(s) is deterministic

In a wireless communication system supporting an unlicensed band, onecell (or carrier (e.g., CC)) or BWP configured for a UE may be awideband having a larger bandwidth (BW) than in legacy LTE. However, aBW requiring CCA based on an independent LBT operation may be limitedaccording to regulations. Let a subband (SB) in which LBT isindividually performed be defined as an LBT-SB. Then, a plurality ofLBT-SBs may be included in one wideband cell/BWP. A set of RBs includedin an LBT-SB may be configured by higher-layer (e.g., RRC) signaling.Accordingly, one or more LBT-SBs may be included in one cell/BWP basedon (i) the BW of the cell/BWP and (ii) RB set allocation information. Aplurality of LBT-SBs may be included in the BWP of a cell (or carrier).An LBT-SB may be, for example, a 20-MHz band. The LBT-SB may include aplurality of contiguous (P)RBs in the frequency domain, and thus may bereferred to as a (P)RB set.

In Europe, two LBT operations are defined: frame based equipment (FBE)and load based equipment (LBE). In FBE, one fixed frame is made up of achannel occupancy time (e.g., 1 to 10 ms), which is a time period duringwhich once a communication node succeeds in channel access, thecommunication node may continue transmission, and an idle periodcorresponding to at least 5% of the channel occupancy time, and CCA isdefined as an operation of observing a channel during a CCA slot (atleast 20 us) at the end of the idle period. The communication nodeperforms CCA periodically on a fixed frame basis. When the channel isunoccupied, the communication node transmits during the channeloccupancy time, whereas when the channel is occupied, the communicationnode defers the transmission and waits until a CCA slot in the nextperiod.

In LBE, the communication node may set q∈{4, 5, . . . , 32} and thenperform CCA for one CCA slot. When the channel is unoccupied in thefirst CCA slot, the communication node may secure a time period of up to( 13/32)q ms and transmit data in the time period. When the channel isoccupied in the first CCA slot, the communication node randomly selectsN∈{1, 2, . . . , q}, stores the selected value as an initial value, andthen senses a channel state on a CCA slot basis. Each time the channelis unoccupied in a CCA slot, the communication node decrements thestored counter value by 1. When the counter value reaches 0, thecommunication node may secure a time period of up to ( 13/32)q ms andtransmit data.

An eNB/gNB or UE of an LTE/NR system should also perform LBT for signaltransmission in an unlicensed band (referred to as a U-band forconvenience). When the eNB or UE of the LTE/NR system transmits asignal, other communication nodes such as a Wi-Fi node should alsoperform LBT so as not to cause interference with transmission by the eNBor the UE. For example, in the Wi-Fi standard (801.11ac), a CCAthreshold is defined as −62 dBm for a non-Wi-Fi signal and −82 dBm for aWi-Fi signal. For example, when the non-Wi-Fi signal is received by astation (STA) or an access point (AP) with a power of more than −62 dBm,the STA or AP does not transmit other signals in order not to causeinterference.

A UE performs a Type 1 or Type 2 CAP for a UL signal transmission in anunlicensed band. In general, the UE may perform a CAP (e.g., Type 1 orType 2) configured by a BS, for a UL signal transmission. For example,CAP type indication information may be included in a UL grant (e.g., DCIformat 0_0 or DCI format 0_1) that schedules a PUSCH transmission.

In the Type 1 UL CAP, the length of a time period spanned by sensingslots sensed as idle before transmission(s) is random. The Type 1 UL CAPmay be applied to the following transmissions.

-   -   PUSCH/SRS transmission(s) scheduled and/or configured by BS    -   PUCCH transmission(s) scheduled and/or configured by BS    -   Transmission(s) related to random access procedure (RAP)

FIG. 9 illustrates Type 1 CAP among channel access procedures of a UEfor UL/DL signal transmission in a U-band applicable to the presentdisclosure.

First, UL signal transmission in the U-band will be described withreference to FIG. 9 .

The UE may sense whether a channel is idle for a sensing slot durationin a defer duration T_(d). After a counter N is decremented to 0, the UEmay perform a transmission (S934). The counter N is adjusted by sensingthe channel for additional slot duration(s) according to the followingprocedure.

Step 1) Set N=N_(init) where N_(init) is a random number uniformlydistributed between 0 and CW_(p), and go to step 4 (S920).

Step 2) If N>0 and the UE chooses to decrement the counter, set N=N−1(S940).

Step 3) Sense the channel for an additional slot duration, and if theadditional slot duration is idle (Y), go to step 4. Else (N), go to step5 (S950).

Step 4) If N=0 (Y) (S930), stop CAP (S932). Else (N), go to step 2.

Step 5) Sense the channel until a busy sensing slot is detected withinthe additional defer duration T_(d) or all slots of the additional deferduration T_(d) are sensed as idle (S960).

Step 6) If the channel is sensed as idle for all slot durations of theadditional defer duration T_(d) (Y), go to step 4. Else (N), go to step5 (S970).

Table 8 illustrates that m_(p), a minimum CW, a maximum CW, a maximumchannel occupancy time (MCOT), and an allowed CW size applied to a CAPvary according to channel access priority classes.

TABLE 8 Channel Access Priority allowed Class (p) mp CWmin, p CWmax, pTulmcot, p CWp sizes 1 2 3 7 2 ms {3, 7}  2 2 7 15 4 ms {7, 15} 3 3 151023 6 or 10 ms {15, 31, 63, 127, 255, 511, 1023} 4 7 15 1023 6 or 10 ms{15, 31, 63, 127, 255, 511, 1023}

The defer duration T_(d) includes a duration T_(f) (16 us) immediatelyfollowed by m_(p) consecutive slot durations where each slot durationT_(sl) is 9 us, and T_(f) includes a sensing slot duration T_(sl) at thestart of the 16-us duration. CW_(Wmin,p)<=CW_(p)<=CW_(max,p). CW_(p) isset to CW_(min,p), and may be updated before Step 1 based on anexplicit/implicit reception response to a previous UL burst (e.g.,PUSCH) (CW size update). For example, CW_(p) may be initialized toCW_(min,p) based on an explicit/implicit reception response to theprevious UL burst, may be increased to the next higher allowed value, ormay be maintained to be an existing value.

In the Type 2 UL CAP, the length of a time period spanned by sensingslots sensed as idle before transmission(s) is deterministic. Type 2 ULCAPs are classified into Type 2A UL CAP, Type 2B UL CAP, and Type 2C ULCAP. In the Type 2A UL CAP, the UE may transmit a signal immediatelyafter the channel is sensed as idle during at least a sensing durationT_(short_dl) (=25 us). T_(short_dl) includes a duration Tf (=16 us) andone immediately following sensing slot duration. In the Type 2A UL CAP,T_(f) includes a sensing slot at the start of the duration. In the Type2B UL CAP, the UE may transmit a signal immediately after the channel issensed as idle during a sensing slot duration T_(f) (=16 us). In theType 2B UL CAP, T_(f) includes a sensing slot within the last 9 us ofthe duration. In the Type 2C UL CAP, the UE does not sense a channelbefore a transmission.

To allow the UE to transmit UL data in the unlicensed band, the BSshould succeed in an LBT operation to transmit a UL grant in theunlicensed band, and the UE should also succeed in an LBT operation totransmit the UL data. That is, only when both of the BS and the UEsucceed in their LBT operations, the UE may attempt the UL datatransmission. Further, because a delay of at least 4 msec is involvedbetween a UL grant and scheduled UL data in the LTE system, earlieraccess from another transmission node coexisting in the unlicensed bandduring the time period may defer the scheduled UL data transmission ofthe UE. In this context, a method of increasing the efficiency of ULdata transmission in an unlicensed band is under discussion.

To support a UL transmission having a relatively high reliability and arelatively low time delay, NR also supports CG type 1 and CG type 2 inwhich the BS preconfigures time, frequency, and code resources for theUE by higher-layer signaling (e.g., RRC signaling) or both ofhigher-layer signaling and L1 signaling (e.g., DCI). Without receiving aUL grant from the BS, the UE may perform a UL transmission in resourcesconfigured with type 1 or type 2. In type 1, the periodicity of a CG, anoffset from SFN=0, time/frequency resource allocation, a repetitionnumber, a DMRS parameter, an MCS/TB size (TBS), a power controlparameter, and so on are all configured only by higher-layer signalingsuch as RRC signaling, without L1 signaling. Type 2 is a scheme ofconfiguring the periodicity of a CG and a power control parameter byhigher-layer signaling such as RRC signaling and indicating informationabout the remaining resources (e.g., the offset of an initialtransmission timing, time/frequency resource allocation, a DMRSparameter, and an MCS/TBS) by activation DCI as L1 signaling.

The biggest difference between autonomous uplink (AUL) of LTE LAA and aCG of NR is a HARQ-ACK feedback transmission method for a PUSCH that theUE has transmitted without receiving a UL grant and the presence orabsence of UCI transmitted along with the PUSCH. While a HARQ process isdetermined by an equation of a symbol index, a symbol periodicity, andthe number of HARQ processes in the CG of NR, explicit HARQ-ACK feedbackinformation is transmitted in AUL downlink feedback information(AUL-DFI) in LTE LAA. Further, in LTE LAA, UCI including informationsuch as a HARQ ID, an NDI, and an RV is also transmitted in AUL UCIwhenever AUL PUSCH transmission is performed. In the case of the CG ofNR, the BS identifies the UE by time/frequency resources and DMRSresources used for PUSCH transmission, whereas in the case of LTE LAA,the BS identifies the UE by a UE ID explicitly included in the AUL UCItransmitted together with the PUSCH as well as the DMRS resources.

Now, DL signal transmission in the U-band will be described withreference to FIG. 9 .

The BS may perform one of the following U-band access procedures (e.g.,channel access procedures (CAPs)) to transmit a DL signal in the U-band.

(1) Type 1 DL CAP Method

In a Type 1 DL CAP, the length of a time duration spanned by sensingslots that are sensed to be idle before transmission(s) is random. TheType 1 DL CAP may be applied to the following transmissions:

-   -   transmission(s) initiated by the BS, including (i) a unicast        PDSCH with user plane data, or (ii) a unicast PDSCH with user        plane data and a unicast PDCCH scheduling the user plane data;        or    -   transmission(s) initiated by the BS, including (i) only a        discovery burst, or (ii) a discovery burst multiplexed with        non-unicast information.

Referring to FIG. 9 , the BS may first sense whether a channel is idlefor a sensing slot duration of a defer duration Td. Next, if a counter Nis decremented to 0, transmission may be performed (S934). The counter Nis adjusted by sensing the channel for additional slot duration(s)according to the following procedures.

Step 1) Set N=Ninit where Ninit is a random number uniformly distributedbetween 0 and CWp, and go to step 4 (S920).

Step 2) If N>0 and the BS chooses to decrement the counter, set N=N−1(S940).

Step 3) Sense the channel for an additional slot duration, and if theadditional slot duration is idle (Y), go to step 4. Else (N), go to step5 (S950).

Step 4) If N=0 (Y), stop a CAP (S1232 (? S932)). Else (N), go to step 2(S930).

Step 5) Sense the channel until a busy sensing slot is detected withinthe additional defer duration Td or all slots of the additional deferduration Td are sensed to be idle (S960).

Step 6) If the channel is sensed to be idle for all slot durations ofthe additional defer duration Td (Y), go to step 4. Else (N), go to step5 (S970).

Table 9 illustrates that mp, a minimum CW, a maximum CW, an MCOT, and anallowed CW size, which are applied to a CAP, vary according to channelaccess priority classes.

TABLE 9 Channel Access Priority allowed Class (p) m_(p) CWmin, p CWmax,p Tmcot, p CWp sizes 1 1 3 7 2 ms {3, 7}  2 1 7 15 3 ms {7, 15} 3 3 1563 8 or 10 ms {15, 31, 63} 4 7 15 1023 8 or 10 ms {15, 31, 63, 127, 255,511, 1023}

The defer duration Td includes a duration Tf (16 μs) immediatelyfollowed by mp consecutive sensing slot durations where each sensingslot duration Tsl is 9 μs, and Tf includes the sensing slot duration Tslat the start of the 16-μs duration.

CWmin,p<=CWp<=CWmax,p. CWp is set to CWmin,p, and may be updated (CWsize update) before Step 1 based on HARQ-ACK feedback (e.g., ratio ofACK signals or NACK signals) for a previous DL burst (e.g., PDSCH). Forexample, CWp may be initialized to CWmin,p based on HARQ-ACK feedbackfor the previous DL burst, may be increased to the next highest allowedvalue, or may be maintained at an existing value.

(2) Type 2 DL CAP Method

In a Type 2 DL CAP, the length of a time duration spanned by sensingslots sensed to be idle before transmission(s) is deterministic. Type 2DL CAPs are classified into Type 2A DL CAP, Type 2B DL CAP, and Type 2CDL CAP.

The Type 2A DL CAP may be applied to the following transmissions. In theType 2A DL CAP, the BS may transmit a signal immediately after a channelis sensed to be idle during at least a sensing duration Tshort_dl=25 μs.Tshort_dl includes a duration Tf (=16 μs) and one immediately followingsensing slot duration. Tf includes the sensing slot at the start of theduration.

-   -   Transmission(s) initiated by the BS, including (i) only a        discovery burst, or (ii) a discovery burst multiplexed with        non-unicast information, or    -   Transmission(s) of the BS after a gap of 25 μs from        transmission(s) by the UE within shared channel occupancy.

The Type 2B DL CAP is applicable to transmission(s) performed by the BSafter a gap of 16 μs from transmission(s) by the UE within sharedchannel occupancy. In the Type 2B DL CAP, the BS may transmit a signalimmediately after a channel is sensed to be idle during Tf=16 μs. Tfincludes a sensing slot within the last 9 μs of the duration. The Type2C DL CAP is applicable to transmission(s) performed by the BS after amaximum of a gap of 16 μs from transmission(s) by the UE within sharedchannel occupancy. In the Type 2C DL CAP, the BS does not sense achannel before performing transmission.

In a wireless communication system supporting a U-band, one cell (orcarrier (e.g., CC)) or BWP configured for the UE may consist of awideband having a larger BW than in legacy LTE. However, a BW requiringCCA based on an independent LBT operation may be limited according toregulations. If a subband (SB) in which LBT is individually performed isdefined as an LBT-SB, a plurality of LBT-SBs may be included in onewideband cell/BWP. A set of RBs constituting an LBT-SB may be configuredby higher-layer (e.g., RRC) signaling. Accordingly, one or more LBT-SBsmay be included in one cell/BWP based on (i) the BW of the cell/BWP and(ii) RB set allocation information.

FIG. 10 illustrates that a plurality of LBT-SBs is included in a U-band.

Referring to FIG. 10 , a plurality of LBT-SBs may be included in the BWPof a cell (or carrier). An LBT-SB may be, for example, a 20-MHz band.The LBT-SB may include a plurality of contiguous (P)RBs in the frequencydomain and thus may be referred to as a (P)RB set. Although notillustrated, a guard band (GB) may be included between the LBT-SBs.Therefore, the BWP may be configured in the form of {LBT-SB #0 (RB set#0)+GB #0+LBT-SB #1 (RB set #1+GB #1)+ . . . +LBT-SB #(K−1) (RB set(#K−1))}. For convenience, LBT-SB/RB indexes may be configured/definedto be increased as a frequency band becomes higher starting from a lowfrequency band.

In the NR system, a massive multiple input multiple output (MIMO)environment in which the number of transmission/reception (Tx/Rx)antennas is significantly increased may be under consideration. That is,as the massive MIMO environment is considered, the number of Tx/Rxantennas may be increased to a few tens or hundreds. The NR systemsupports communication in an above 6 GHz band, that is, a millimeterfrequency band. However, the millimeter frequency band is characterizedby the frequency property that a signal is very rapidly attenuatedaccording to a distance due to the use of too high a frequency band.Therefore, in an NR system operating at or above 6 GHz, beamforming (BF)is considered, in which a signal is transmitted with concentrated energyin a specific direction, not omni-directionally, to compensate for rapidpropagation attenuation. Accordingly, there is a need for hybrid BF withanalog BF and digital BF in combination according to a position to whicha BF weight vector/precoding vector is applied, for the purpose ofincreased performance, flexible resource allocation, and easiness offrequency-wise beam control in the massive MIMO environment.

FIG. 11 is a block diagram illustrating an exemplary transmitter andreceiver for hybrid BF.

To form a narrow beam in the millimeter frequency band, a BF method ismainly considered, in which a BS or a UE transmits the same signalthrough multiple antennas by applying appropriate phase differences tothe antennas and thus increasing energy only in a specific direction.Such BF methods include digital BF for generating a phase difference fordigital baseband signals, analog BF for generating phase differences byusing time delays (i.e., cyclic shifts) for modulated analog signals,and hybrid BF with digital BF and analog beamforming in combination. Useof a radio frequency (RF) unit (or transceiver unit (TXRU)) for antennaelement to control transmission power and phase control on antennaelement basis enables independent BF for each frequency resource.However, installing TXRUs in all of about 100 antenna elements is lessfeasible in terms of cost. That is, a large number of antennas arerequired to compensate for rapid propagation attenuation in themillimeter frequency, and digital BF needs as many RF components (e.g.,digital-to-analog converters (DACs), mixers, power amplifiers, andlinear amplifiers) as the number of antennas. As a consequence,implementation of digital BF in the millimeter frequency band increasesthe prices of communication devices. Therefore, analog BF or hybrid BFis considered, when a large number of antennas are needed as is the casewith the millimeter frequency band. In analog BF, a plurality of antennaelements are mapped to a single TXRU and a beam direction is controlledby an analog phase shifter. Because only one beam direction is generatedacross a total band in analog BF, frequency-selective BF may not beachieved with analog BF. Hybrid BF is an intermediate form of digital BFand analog BF, using B RF units fewer than Q antenna elements. In hybridBF, the number of beam directions available for simultaneoustransmission is limited to B or less, which depends on how B RF unitsand Q antenna elements are connected.

Beam Management (BM)

The BM refers to a series of processes for acquiring and maintaining aset of BS beams (transmission and reception point (TRP) beams) and/or aset of UE beams available for DL and UL transmission/reception. The BMmay include the following processes and terminology.

-   -   Beam measurement: an operation by which the BS or UE measures        the characteristics of a received beamformed signal    -   Beam determination: an operation by which the BS or UE selects        its Tx/Rx beams    -   Beam sweeping: an operation of covering a spatial domain by        using Tx and/or Rx beams for a prescribed time interval        according to a predetermined method    -   Beam report: an operation by which the UE reports information        about a signal beamformed based on the beam measurement.

The BM procedure may be divided into (1) a DL BM procedure using an SSBor CSI-RS and (2) a UL BM procedure using an SRS. Further, each BMprocedure may include Tx beam sweeping for determining a Tx beam, and Rxbeam sweeping for determining an Rx beam.

The DL BM procedure may include (1) transmission of beamformed DL RSs(e.g., CSI-RS or SSB) from the BS and (2) beam reporting from the UE.

A beam report may include preferred DL RS ID(s) and reference signalreceived power(s) (RSRP(s)) corresponding to the preferred DL RS ID(s).A DL RS ID may be an SSB resource indicator (SSBRI) or a CSI-RS resourceindicator (CRI).

FIG. 12 is a diagram illustrating exemplary BF using an SSB and aCSI-RS.

Referring to FIG. 12 , an SSB beam and a CSI-RS beam may be used forbeam measurement. A measurement metric is the RSRP of eachresource/block. The SSB may be used for coarse beam measurement, whereasthe CSI-RS may be used for fine beam measurement. The SSB may be usedfor both Tx beam sweeping and Rx beam sweeping. SSB-based Rx beamsweeping may be performed by attempting to receive the SSB for the sameSSBRI, while changing an Rx beam across multiple SSB bursts at a UE. OneSS burst includes one or more SSBs, and one SS burst set includes one ormore SSB bursts.

1. DL BM Using SSB

FIG. 13 is a diagram illustrating a signal flow for an exemplary DL BMprocedure using an SSB.

An SSB-based beam report is configured during CSI/beam configuration inRRC_CONNECTED mode.

-   -   A UE receives a CSI-ResourceConfig information element (IE)        including CSI-SSB-ResourceSetList for SSB resources used for BM        from a BS (S1310). The RRC parameter, CSI-SSB-ResourceSetList is        a list of SSB resources used for BM and reporting in one        resource set. The SSB resource set may be configured as {SSBx1,        SSBx2, SSBx3, SSBx4}. SSB indexes may range from 0 to 63.    -   The UE receives signals in the SSB resources from the BS based        on CSI-SSB-ResourceSetList (S1320).    -   When CSI-RS reportConfig related to an SSBRI and RSRP reporting        has been configured, the UE reports a best SSBRI and an RSRP        corresponding to the best SSBRI to the BS (S1330). For example,        when reportQuantity in the CSI-RS reportConfig IE is set to        ‘ssb-Index-RSRP’, the UE reports the best SSBRI and the RSRP        corresponding to the best SSBRI to the BS.

When CSI-RS resources are configured in OFDM symbol(s) carrying an SSBand ‘QCL-TypeD’ is applicable to the CSI-RS resources and the SSB, theUE may assume that a CSI-RS and the SSB are quasi-co-located (QCLed)from the perspective of ‘QCL-TypeD’. QCL-TypeD may mean that antennaports are QCLed from the perspective of spatial Rx parameters. When theUE receives signals from a plurality of DL antenna ports placed in theQCL-TypeD relationship, the UE may apply the same Rx beam to the signals

2. DL BM Using CSI-RS

The CSI-RS serves the following purposes: i) when Repetition isconfigured and TRS_info is not configured for a specific CSI-RS resourceset, the CSI-RS is used for BM; ii) when Repetition is not configuredand TRS_info is configured for the specific CSI-RS resource set, theCSI-RS is used for a tracking reference signal (TRS); and iii) wheneither of Repetition or TRS_info is configured for the specific CSI-RSresource set, the CSI-RS is used for CSI acquisition.

When (the RRC parameter) Repetition is set to ‘ON’, this is related tothe Rx beam sweeping process of the UE. In the case where Repetition isset to ‘ON’, when the UE is configured with NZP-CSI-RS-ResourceSet, theUE may assume that signals in at least one CSI-RS resource withinNZP-CSI-RS-ResourceSet are transmitted through the same DL spatialdomain filter. That is, the at least one CSI-RS resource withinNZP-CSI-RS-ResourceSet is transmitted on the same Tx beam. The signalsin the at least one CSI-RS resource within NZP-CSI-RS-ResourceSet may betransmitted in different OFDM symbols.

On the contrary, when Repetition is set to ‘OFF’, this is related to theTx beam sweeping process of the BS. In the case where Repetition is setto ‘OFF’, the UE does not assume that signals in at least one CSI-RSresource within NZP-CSI-RS-ResourceSet are transmitted through the sameDL spatial domain filter. That is, the signals in the at least oneCSI-RS resource within NZP-CSI-RS-ResourceSet are transmitted ondifferent Tx beams. FIG. 12 illustrates another exemplary DL BMprocedure using a CSI-RS.

FIG. 14(a) illustrates an Rx beam refinement process of a UE, and FIG.14(b) illustrates a Tx beam sweeping process of a BS. Further, FIG.14(a) is for a case in which Repetition is set to ‘ON’, and FIG. 14(b)is for a case in which Repetition is set to ‘OFF’.

With reference to FIGS. 14(a) and 15(a), an Rx beam determinationprocess of a UE will be described below.

FIG. 15(a) is a diagram illustrating a signal flow for an exemplary Rxbeam determination process of a UE.

-   -   The UE receives an NZP CSI-RS resource set IE including an RRC        parameter ‘Repetition’ from a BS by RRC signaling (S1510). The        RRC parameter ‘Repetition’ is set to ‘ON’ herein.    -   The UE repeatedly receives signals in resource(s) of a CSI-RS        resource set for which the RRC parameter ‘Repetition’ is set to        ‘ON’ on the same Tx beam (or DL spatial domain Tx filter) of the        BS in different OFDM symbols (S1520).    -   The UE determines its Rx beam (S1530).    -   The UE skips CSI reporting (S1540). That is, the UE may skip CSI        reporting, when the RRC parameter ‘Repetition’ is set to ‘ON’.

With reference to FIGS. 14(b) and 15(b), a Tx beam determination processof a BS will be described below.

FIG. 15(b) is a diagram illustrating an exemplary Tx beam determinationprocess of a BS.

-   -   A UE receives an NZP CSI-RS resource set IE including an RRC        parameter ‘Repetition’ from the BS by RRC signaling (S1550).        When the RRC parameter ‘Repetition’ is set to ‘OFF’, this is        related to a Tx beam sweeping process of the BS.    -   The UE receives signals in resource(s) of a CSI-RS resource set        for which the RRC parameter ‘Repetition’ is set to ‘OFF’ on        different Tx beams (or DL spatial domain Tx filters) of the BS        (S1560).    -   The UE selects (or determines) a best beam (S1570).    -   The UE reports the ID (e.g., CRI) of the selected beam and        related quality information (e.g., an RSRP) to the BS (S1580).        That is, the UE reports a CRI and an RSRP corresponding to the        CRI, when a CSI-RS is transmitted for BM.

FIG. 16 is a diagram illustrating exemplary resource allocation in thetime and frequency domains, which is related to the operation of FIG. 14.

When Repetition is set to ‘ON’ for a CSI-RS resource set, a plurality ofCSI-RS resources may be repeatedly used on the same Tx beam, whereaswhen Repetition is set to ‘OFF’ for the CSI-RS resource set, differentCSI-RS resources may be repeatedly transmitted on different Tx beams.

3. DL BM-Related Beam Indication

The UE may receive at least a list of up to M candidate transmissionconfiguration indication (TCI) states for QCL indication by RRCsignaling. M depends on a UE capability and may be 64.

Each TCI state may be configured with one RS set. Table 7 describes anexample of a TCI-State IE. The TC-State IE is related to a QCL typecorresponding to one or two DL RSs.

TABLE 10 -- ASN1START -- TAG-TCI-STATE-START TCI-State ::= SEQUENCE {tci-StateId TCI-StateId, qcl-Type1 QCL-Info, qcl-Type2 QCL-InfoOPTIONAL,  -- Need R ... } QCL-Info ::= SEQUENCE { cell ServCellIndexOPTIONAL, -- Need R bwp-Id BWP-Id OPTIONAL, -- Cond CSI-RS-IndicatedreferenceSignal CHOICE { csi-rs NZP-CSI-RS-ResourceId, ssb SSB-Index },qcl-Type ENUMERATED {typeA, typeB, typeC, typeD}, ... } --TAG-TCI-STATE-STOP -- ASN1STOP

In Table 10, ‘bwp-Id’ identifies a DL BWP in which an RS is located,‘cell’ indicates a carrier in which the RS is located, and‘referencesignal’ indicates reference antenna port(s) serving as a QCLsource for target antenna port(s) or an RS including the referenceantenna port(s). The target antenna port(s) may be for a CSI-RS, PDCCHDMRS, or PDSCH DMRS.

4. Quasi-Co Location (QCL)

The UE may receive a list of up to M TCI-State configurations to decodea PDSCH according to a detected PDCCH carrying DCI intended for a givencell. M depends on a UE capability.

As described in Table 10, each TCI-State includes a parameter forestablishing the QCL relationship between one or more DL RSs and a PDSCHDM-RS port. The QCL relationship is established with an RRC parameterqcl-Type1 for a first DL RS and an RRC parameter qcl-Type2 for a secondDL RS (if configured).

The QCL type of each DL RS is given by a parameter ‘qcl-Type’ includedin QCL-Info and may have one of the following values.

-   -   ‘QCL-TypeA’: {Doppler shift, Doppler spread, average delay,        delay spread}    -   ‘QCL-TypeB’: {Doppler shift, Doppler spread}    -   ‘QCL-TypeC’: {Doppler shift, average delay}    -   ‘QCL-TypeD’: {Spatial Rx parameter}

For example, if a target antenna port is for a specific NZP CSI-RS, theNZP CSI-RS antenna port may be indicated/configured as QCLed with aspecific TRS from the perspective of QCL-Type A and with a specific SSBfrom the perspective of QCL-Type D. Upon receipt of thisindication/configuration, the UE may receive the NZP CSI-RS using aDoppler value and a delay value which are measured in a QCL-TypeA TRS,and apply an Rx beam used to receive a QCL-Type D SSB for reception ofthe NZP CSI-RS.

UL BM Procedure

In UL BM, beam reciprocity (or beam correspondence) between Tx and Rxbeams may or may not be established according to the implementation ofthe UE. If the Tx-Rx beam reciprocity is established at both the BS andUE, a UL beam pair may be obtained from a DL beam pair. However, if theTx-Rx beam reciprocity is established at neither the BS nor UE, aprocess for determining a UL beam may be required separately fromdetermination of a DL beam pair.

In addition, even when both the BS and UE maintain the beamcorrespondence, the BS may apply the UL BM procedure to determine a DLTx beam without requesting the UE to report its preferred beam.

The UL BM may be performed based on beamformed UL SRS transmission.Whether the UL BM is performed on a set of SRS resources may bedetermined by a usage parameter (RRC parameter). If the usage isdetermined as BM, only one SRS resource may be transmitted for each of aplurality of SRS resource sets at a given time instant.

The UE may be configured with one or more SRS resource sets (through RRCsignaling), where the one or more SRS resource sets are configured bySRS-ResourceSet (RRC parameter). For each SRS resource set, the UE maybe configured with K≥1 SRS resources, where K is a natural number, andthe maximum value of K is indicated by SRS_capability.

The UL BM procedure may also be divided into Tx beam sweeping at the UEand Rx beam sweeping at the BS similarly to DL BM.

FIG. 17 illustrates an example of a UL BM procedure based on an SRS.

FIG. 17(a) shows a process in which the BS determines Rx beamforming,and FIG. 17(b) shows a process in which the UE performs Tx beamsweeping.

FIG. 18 is a flowchart illustrating an example of a UL BM procedurebased on an SRS.

-   -   The UE receives RRC signaling (e.g., SRS-Config IE) including a        usage parameter (RRC parameter) set to BM from the BS (S1810).        The SRS-Config IE is used to configure SRS transmission. The        SRS-Config IE includes a list of SRS resources and a list of SRS        resource sets. Each SRS resource set refers to a set of SRS        resources.    -   The UE determines Tx beamforming for SRS resources to be        transmitted based on SRS-SpatialRelation Info included in the        SRS-Config IE (S1820). Here, the SRS-SpatialRelation Info is        configured for each SRS resource and indicates whether the same        beamforming as that used for an SSB, a CSI-RS, or an SRS is        applied for each SRS resource.    -   If SRS-SpatialRelationInfo is configured for the SRS resources,        the same beamforming as that used in the SSB, CSI-RS, or SRS is        applied and transmitted. However, if SRS-SpatialRelationInfo is        not configured for the SRS resources, the UE randomly determines        the Tx beamforming and transmits an SRS based on the determined        Tx beamforming (S1830).

For a P-SRS in which ‘SRS-ResourceConfigType’ is set to ‘periodic’:

i) If SRS-SpatialRelationInfo is set to ‘SSB/PBCH’, the UE transmits thecorresponding SRS by applying the same spatial domain transmissionfilter as a spatial domain reception filter used for receiving theSSB/PBCH (or a spatial domain transmission filter generated from thespatial domain reception filter);

ii) If SRS-SpatialRelationInfo is set to ‘CSI-RS’, the UE transmits theSRS by applying the same spatial domain transmission filter as that usedfor receiving the CSI-RS; or

iii) If SRS-SpatialRelationInfo is set to ‘SRS’, the UE transmits thecorresponding SRS by applying the same spatial domain transmissionfilter as that used for transmitting the SRS.

-   -   Additionally, the UE may or may not receive feedback on the SRS        from the BS as in the following three cases (S1840).

i) When Spatial_Relation_Info is configured for all SRS resources in anSRS resource set, the UE transmits the SRS on a beam indicated by theBS. For example, if Spatial_Relation_Info indicates the same SSB, CRI,or SRI, the UE repeatedly transmits the SRS on the same beam.

ii) Spatial_Relation_Info may not be configured for all SRS resources inthe SRS resource set. In this case, the UE may transmit while changingthe SRS beamforming randomly.

iii) Spatial_Relation_Info may be configured only for some SRS resourcesin the SRS resource set. In this case, the UE may transmit the SRS on anindicated beam for the configured SRS resources, but for SRS resourcesin which Spatial_Relation_Info is not configured, the UE may performtransmission by applying random Tx beamforming.

In proposed methods to be described later, a beam may mean an area forperforming a specific operation (e.g., LBT or transmission) byconcentrating power in a specific direction and/or in a specific space.In other words, the UE or the BS may perform an operation such as LBT ortransmission by targeting a specific area (i.e., a beam) correspondingto a specific space and/or a specific direction. Thus, each beam maycorrespond to each space and/or each direction. In addition, the UE orthe BS may use a spatial domain filter corresponding to each spaceand/or each direction in order to use each beam. That is, one spatialdomain filter may correspond to one or more beams. The UE or the BS mayperform an operation such as LBT or transmission using the spatialdomain filter corresponding to a beam (or space and/or direction) to beused.

For example, the UE or the BS may perform LBT using a spatial domainfilter corresponding to an LBT beam in a space and/or a direction forthe corresponding LBT beam or perform DL/UL transmission using a spatialdomain filter corresponding to a Tx beam in a space and/or a directionfor the corresponding Tx beam.

In a high-frequency band of 52.6 GHz or higher, due to a relativelylarger path loss than in a low-frequency band, omnidirectional LBT(hereinafter, O-LBT) for performing LBT in all directions,omnidirectional transmission and reception, directional LBT(hereinafter, D-LBT) for performing LBT only in a specific beamdirection, and directional transmission and reception, through atechnique such as analog beamforming using multiple antennas, may beconsidered.

In this case, since O-LBT and D-LBT are different in terms of an areaand a direction in which LBT is performed, it is necessary todifferently configure an energy detection (ED) threshold for determiningwhether a channel is in an idle or busy state through energymeasurement. In addition, since LBT has directionality, a direction inwhich LBT is performed and the ED threshold are closely related witheach other when beams of different directions are multiplexed within aCOT obtained through success of D-LBT or when DL/UL beams are used forDL/UL transmission and reception through DL/UL switching. Accordingly, amethod of configuring a proper ED threshold and performing multiplexingis needed.

A typical CAP performed for transmission in a U-band is LBT. LBT is amechanism that prevents collision between transmissions by allowingtransmission of a corresponding signal when a noise level is less than acertain level as a result of comparing a surrounding interference levelmeasured by the BS and/or the UE that is to transmit signals with aspecific threshold such as an ED threshold.

FIG. 19 illustrates exemplary D-LBT and exemplary O-LBT.

FIG. 19(a) illustrates D-LBT including specific beam direction LBTand/or beam group unit LBT, and FIG. 19(b) illustrates O-LBT.

In a legacy NR-U system (e.g., Rel-16 NR-U), a DL/UL signal/channel hasbeen transmitted if it is determined that a channel is idle byperforming a CAP (i.e., LBT) as described with reference to FIG. 9 . Onthe other hand, in the legacy NR-U system, an LBT band has been alignedwith LBT bands of other RATs for coexistence with other RATs (e.g.,Wi-Fi), and the CAP (i.e., LBT) has been performed omnidirectionally. Inother words, non-directional LBT has been performed in the legacy NR-Usystem.

However, Rel-17 NR-U for transmitting the DL/UL signal/channel in ahigher band (e.g., a band of 52.6 GHz or higher) than a U-band of 7 GHzused in the legacy NR-U system may utilize D-LBT which transmits thesignal/channel by concentrating energy in a specific beam direction inorder to overcome path loss larger than in the band of 7 GHz used in thelegacy system. That is, in Rel-17 NR-U, the DL/UL signal/channel may betransmitted over wider coverage by reducing path loss through D-LBT, andefficiency may be improved even in coexistence with other RATs (e.g.,WiGig).

Referring to FIG. 19(a), when a beam group consists of beams #1 to #5,performing LBT based on beams #1 to #5 may be referred to as beam groupunit LBT. In addition, performing LBT through any one (e.g., beam #3) ofbeams #1 to #5 may be referred to as specific beam direction LBT. Inthis case, beams #1 to #5 may be continuous (or adjacent) beams but mayalso be discontinuous (or non-adjacent) beams. Further, the number ofbeams included in the beam group is not necessarily plural, and a singlebeam may form one beam group.

FIG. 19(b) illustrates O-LBT. When omnidirectional beams constitute onebeam group and perform LBT in units of the corresponding beam group,this may be interpreted as performing O-LBT. In other words, if beams ofall directions, i.e., omnidirectional beams which are a set of beamscovering a specific sector in a cell, are included in one beam group,this may mean O-LBT.

In other words, in the case of a high frequency band, coverage may belimited due to significant path loss. In order to overcome such acoverage problem, a multi-antenna technique may be used. For example,narrow-beam transmission in which a signal is transmitted byconcentrating energy in a specific direction, rather thanomnidirectional transmission, may be performed.

In a high-frequency U-band, along with a CAP such as LBT describedabove, beam-based transmission combined therewith needs to beconsidered. For example, in order to perform D-LBT in a specificdirection, D-LBT may be performed only in the corresponding direction orLBT may be performed in units of a beam group including a beam of thecorresponding direction. Then, if a channel is determined to be idle,transmission may be performed. Here, the beam group may include a singlebeam or a plurality of beams. If the beam group includes omnidirectionalbeams, D-LBT may be extended to O-LBT.

Since beam-based transmission described above transmits a signal byconcentrating energy in a specific direction, interference affectingneighboring BSs/UEs (except for nodes located in a transmissiondirection) may be relatively small as compared with omnidirectionaltransmission. That is, it may be considered that spectrum sharing isnaturally formed in beam-based transmission because beam-basedtransmission causes interference only in a specific direction.Therefore, if a specific condition is satisfied, a channel accessopportunity may be increased and system performance may be improved byperforming beam-based transmission without performing LBT.

Information about a beam group in which each beam is included andinformation about at least one beam included in each beam group may beconfigured, and a CWS and a backoff counter value may be separatelymanaged for each individual beam or each individual beam group.Therefore, when performing LBT, an event such as CWS resetting/increaseor backoff counter decrease may affect each beam and a beam group inwhich each beam is included. For example, if feedback for datatransmitted through LBT in a specific beam direction is NACK and thus aCWS value for the corresponding beam direction is increased, theincrease of the CWS value is also reflected in the CWS managed by thebeam group in which the corresponding beam is included, so that a CWSvalue for the beam group may be increased. On the other hand, even ifthe CWS value for the corresponding beam direction is increased, the CWSvalue for the beam group may be independently managed without affectingthe beam group including the corresponding beam. In addition, thebackoff counter value managed based on each beam or each beam group mayalso be configured as described above such that the back-off countervalue for each beam and the back-off counter value for each beam groupare independently managed or depend on each other to affect each other.

Beam-based LBT and beam group-based LBT may be interchanged under aspecific condition. In the case of UL transmission, the BS may indicatean LBT type to be used among the two LBT types (i.e., beam-based LBT andbeam group-based LBT). In the case of CG UL transmission, whenconfiguring resources for CG UL transmission, an LBT type to beperformed on each resource may be configured as well. If delay-sensitivedata transmission is indicated together with LBT in a specific beamdirection, data may not be transmitted due to LBT failure. Therefore, achannel access opportunity may be increased by allocating a plurality ofLBT opportunities to other beams in a beam group in which thecorresponding beam is included.

In this disclosure, a beam-based LBT procedure or a beam group-based LBTprocedure may basically mean a random backoff-based Cat-3 or Cat-4 LBT.In beam-based LBT, energy measured by performing carrier sensing in aspecific direction is compared with an ED threshold. Next, if the energymeasured by performing carrier sensing is lower than the ED threshold, achannel in the corresponding beam direction may be considered to be idleand, if the energy measured through carrier sensing is higher than theED threshold, the channel in the corresponding beam may be considered tobe busy.

The beam group-based LBT procedure is to perform the above-described LBTprocedure in all beam directions included in a beam group and totransmit signals when LBT is successful by performing a randombackoff-based LBT procedure as a representative using a correspondingbeam, similar to multi-CC LBT when a beam (e.g., a representative beam)of a preconfigured/indicated specific direction is present in a beamgroup and performing non-random backoff-based Cat-1 or Cat-2 LBT for theremaining beams included in the beam group. In the beam group-based LBTprocedure, according to the regulation of each country/region, therandom backoff-based LBT procedure may be performed through therepresentative beam, and no-LBT may be performed on the remaining beamsincluded in the beam group to transmit signals through each of theremaining beams.

Before a description of proposed methods, NR-based channel accessschemes for an unlicensed band used in the present disclosure areclassified as follows.

-   -   Category 1 (Cat-1): the next transmission immediately follows        the previous transmission after a switching gap within a COT,        and the switching gap is shorter than 16 us, including even a        transceiver turn-around time. Cat-1 LBT may correspond to the        above-described Type 2C CAP.    -   Category 2 (Cat-2): an LBT method without backoff. Once a        channel is confirmed to be idle during a specific time period        shortly before transmission, the transmission may be performed        immediately. Cat-2 LBT may be subdivided according to the length        of a minimum sensing duration required for channel sensing        immediately before a transmission. For example, Cat-2 LBT with a        minimum sensing duration of 25 us may correspond to the        above-described Type 2A CAP, and Cat-2 LBT with a minimum        sensing duration of 16 us may correspond to the above-described        Type 2B CAP. The minimum sensing durations are merely exemplary,        and a minimum sensing duration less than 25 us or 16 us (e.g., a        minimum sensing duration of 9 us) may also be available.    -   Category 3 (Cat-3): an LBT method with fixed contention window        size (CWS) i-based backoff. A transmitting entity selects a        random number N in a range of 0 to a (fixed) maximum CWS value        and decrements a counter value each time it determines that a        channel is idle. When the counter value reaches 0, the        transmitting entity is allowed to perform a transmission.    -   Category 4 (Cat-4): an LBT method with variable CWS-based        backoff. A transmitting entity selects a random number N in a        range of 0 to a (variable) maximum CWS value and decrements a        counter value, each time it determines that a channel is idle.        When the counter value reaches 0, the transmitting entity is        allowed to perform a transmission. If the transmitting entity        receives a feedback indicating reception failure of the        transmission, the transmitting entity increases the maximum CWS        value by one level, selects a random number again within the        increased CWS value, and performs an LBT procedure. Cat-4 LBT        may correspond to the above-described Type 1 CAP.

A definition related to QCL described in this disclosure may follow oneof definitions related to QCL described above. Similarly, the definitionof the QCL concept may be modified to a form in which co-locationtransmission between antenna ports for which QCL assumption is made maybe assumed (e.g., the UE may assume that the antenna ports transmitsignals at the same transmission point). The scope of the presentdisclosure includes such similar modified examples. For convenience ofdescription, the above QCL-related definitions are used interchangeablyin the present disclosure.

By the above definition, the UE may not assume that“non-quasi-co-located (NQC) antenna ports” have the same large-scalechannel properties therebetween. That is, in this case, a typical UEreceiver should perform independent processing for each configured NQCantenna port in regard to timing acquisition and tracking, frequencyoffset estimation and compensation, delay estimation, and Dopplerestimation. The UE may advantageously perform the following operationsfor antenna ports for which QCL may be assumed.

-   -   In regard to delay spread and doppler spread, the UE may apply        the same power-delay-profile, delay spread, Doppler spectrum,        and Doppler spread estimation results for one antenna port to a        Wiener filter, etc. used for channel estimation for another        antenna port.    -   In regard to frequency shift and received timing, after        performing time and frequency synchronization for one antenna,        the UE may apply the same synchronization to demodulation for        another antenna port.    -   In regard to average received power, the UE may average RSRP        measurements for a plurality of antenna ports.

Meanwhile, when beam reciprocity is established between DL beams and ULbeams, either a procedure for determining a DL beam pair or a procedurefor determining a UL beam pair may be omitted. This may be equallyapplied even when beam correspondence is established.

Here, “beam reciprocity (or beam correspondence) is established” maymean that it is assumed that a BS Tx beam and a BS Rx beam coincide anda UE Tx beam and a UE Rx beam coincide in communication between the BSand the UE. Here, the BS Tx beam and the BS Rx beam may mean a DL Txbeam and a DL Rx beam, respectively, and the UE Tx beam and the UE Rxbeam may mean a UL Tx beam and a UL Rx beam, respectively. Here, the Txbeam may mean a transmission beam, and the Rx beam may mean a receptionbeam.

It may be desirable for the following reasons to configure all DLsignals/channels (or all UL signals/channels) included in one Tx burstas signals/channels having a spatial (partial) QCL relation. Forexample, in transmitting a Tx burst consisting of a total of 4 slotsafter the BS succeeds in LBT as illustrated in FIG. 20 , the BS maytransmit a signal in 3 slots in a beam direction of A and then transmita signal in the fourth slot in a beam direction of C.

However, while the BS transmits a signal in the beam direction of A, aWi-Fi AP coexisting in a corresponding U-band may fail to detect thesignal transmitted in the beam direction of A and determine that achannel is idle. After succeeding in LBT, the Wi-Fi AP may start totransmit and receive a signal. In this case, if the BS transmits asignal in the beam direction of C starting from slot #k+3, the signalmay act as interference with a corresponding Wi-Fi signal. Thus, whenthe BS that has performed transmission in the direction of A performstransmission by switching a beam direction without additional LBT, theBS may cause interference with another coexisting wireless node.Therefore, it may be desirable not to switch a Tx beam direction of a Txburst that is transmitted after the BS succeeds in LBT.

In the NR system, a method of signalling beam information to be used bythe UE during UL transmission and reception by associating a DL signaland a UL signal is under consideration. For example, if there is a beamdirection generated by the UE on a channel state information referencesignal (CSI-RS) resource by associating the CSI-RS resource and asounding reference signal (SRS) resource, when the UE transmits an SRSon the SRS resource linked with the CSI-RS resource (or when the UEtransmits a PUSCH scheduled through a UL grant through which the SRSresource linked with the CSI-RS resource is signalled), the UE maytransmit the UL signal using a Tx beam corresponding to a CSI-RS Rxbeam. In this case, the relationship between a specific Rx beam and aspecific Tx beam may be configured by the UE in implementation whenthere is beam correspondence capability of the UE. Alternatively, therelationship between the specific Rx beam and the specific Tx beam maybe configured by training of the BS and the UE when there is no beamcorrespondence capability of the UE.

Therefore, when an association relationship between the DL signal andthe UL signal is defined, COT sharing may be allowed between a DL Txburst consisting of DL signals/channels in a spatial (partial) QCLrelation with the DL signal and a UL Tx burst consisting of ULsignals/channels in a spatial (partial) QCL relation with the UL signalassociated with the DL signal.

Here, the UL signals/channels may include at least one or more of thefollowing signals/channels:

-   -   an SRS, a demodulation reference signal (DMRS) for a PUCCH, a        DMRS for a PUSCH, a PUCCH, a PUSCH, or a PRACH

Here, the DL signals/channels may include at least one or more of thefollowing signals/channels:

-   -   a PSS, an SSS, a DMRS for a PBCH, a PBCH, a tracking reference        signal (TRS), a CSI-RS for tracking, a CSI-RS for CSI        acquisition, a CSI-RS for radio resource management (RRM)        measurement, a CSI-RS for BM, a DMRS for a PDCCH, a DMRS for a        PDSCH, a PDCCH (or a control resource set (CORESET) in which the        PDCCH may be transmitted), a PDSCH, or a signal introduced for        the purpose of tracking, (fine) time/frequency synchronization,        coexistence, power saving, or frequency reuse factor=1, arranged        in front of a Tx burst, as a modified signal of the above-listed        signals or related signals or as a newly introduced signal

Meanwhile, each proposed method to be described later may be combinedwith other proposed methods and be applied together therewith unlesseach proposed method conflicts with other proposed methods.

As described above, in the U-band, signal transmission should follow arule of “LBT” by a CCA operation. That is, a transmitter may performsignal transmission when a signal equal to or greater than a specificCCA threshold is not detected during a specific sensing period.

Considering the CCA operation, first, since each BS (or TRP) or UEshould always perform “energy sensing” prior to a transmissionoperation, a definition or a restriction condition of an operationsimilar to above energy sensing needs to be specified even from theviewpoint of an Rx antenna of the BS/UE. This is because an energysensing result may be different depending on implementation, such aswhether or not the BS receives a signal through a sectored antenna orwhether or not the BS receives a signal by applying a specific Rx beampattern.

Accordingly, for example, when a gNB Rx beam pattern applied duringenergy sensing and a Tx beam pattern during transmission after CCA aredifferently applied, a beam area in which CCA is determined and a beamarea of a Tx signal are different, so that there is a possibility ofcausing large interference with surrounding communication.

Prior to describing proposed methods, the overall operation processes ofthe UE and the BS for implementing the proposed methods to be describedwill now be described.

FIG. 21 illustrates a method for the UE to transmit a UL signalaccording to at least one proposed method of the present disclosure.

Referring to FIG. 21 , the UE may obtain an ED threshold for energysensing (S2101). For example, the UE may obtain the ED threshold basedon at least one of [Proposed Method #1], [Proposed Method #2], or[Proposed Method #4]. However, the UE may also obtain the ED thresholdby the prior art and methods other than the proposed methods accordingto the present disclosure.

The UE may obtain an LBT-BW (S2103). For example, the UE may obtain theLBT-BW based on [Proposed Method #3]. However, a method of obtaining theLBT-BW according to [Proposed Method #3] may be omitted. If the methodof obtaining the LBT-BW according to [Proposed Method #3] is omitted,the UE may perform LBT based on an LBT-BW (e.g., 20 MHz) according tothe prior art or perform LBT using a configured BWP size as an LBT-BWunit.

The UE may perform LBT based on the obtained ED threshold and/or LBT-BW(S2105). In addition, upon succeeding in LBT, the UE may transmit the ULsignal to the BS (S2107). For example, the UE may perform LBT based on[Proposed Method #2] for multiplexed Tx beams and transmit the ULsignal.

FIG. 22 illustrates a method for the BS to transmit a DL signalaccording to at least one proposed method of the present disclosure.

Referring to FIG. 22 , the BS may obtain an ED threshold for energysensing (S2201). For example, the BS may acquire the ED threshold basedon at least one of [Proposed Method #1], [Proposed Method #2], or[Proposed Method #4]. However, the BS may also obtain the ED thresholdby the prior art and methods other than the proposed methods accordingto the present disclosure.

The BS may acquire an LBT-BW (S2203). For example, the BS may configurethe LBT-BW based on [Proposed Method #3]. However, a method ofconfiguring the LBT-BW according to [Proposed Method #3] may be omitted.If the method of configuring the LBT-BW according to [Proposed Method#3] is omitted, the BS may perform LBT based on an LBT-BW (e.g., 20 MHz)according to the prior art or perform LBT using a configured BWP size asan LBT-BW unit.

The BS may perform LBT based on the obtained ED threshold and/or LBT-BW(S2205). Upon succeeding in LBT, the BS may transmit the DL signal tothe UE (S2207). For example, the BS may perform LBT for multiplexed Txbeams based on [Proposed Method #2] and transmit the DL signal.

Hereinafter, the proposed methods of the present disclosure for solvingthe above-described problems will be described.

[Proposed Method #1]

When ED measurement-related requirements of the UE are defined (e.g., inthe RAN4 standard), an ED threshold may be configured.

1. Embodiment #1-1

A method of defining an ED measurement type or an ED measurement classfor a specific ED threshold. In this case, the ED threshold may bedifferent according to the ED measurement type/class.

2. Embodiment #1-2

The UE may previously report an ED measurement capability thereof to theBS. The BS may indicate/configure a spatial relation between an LBT beamand a specific RS to/for the UE based on information about the EDmeasurement capability and indicate/configure an ED measurementtype/class and an ED threshold of D-LBT together with UL schedulinginformation.

In this case, the ED threshold may be differently configuredfor/indicated to the UE according to a DL signal which is in a spatialrelation with a UL signal/channel to be transmitted by the UE.

A detailed description of [Proposed Method #1] will now be given.

A CCA range in the case of performing D-LBT through a specific LBT beam(e.g., Rx beam pattern) using a specific directional antenna should notexceed an interference range in which Tx beam(s) affect interference. Inaddition, the interference range in which the Tx beam(s) affectinterference should be considered when the CCA range and an EDT (e.g.,ED threshold) of D-LBT are configured. Meanwhile, ED measurement-relatedrequirements of the UE may be defined in a standard document such asRAN4, and the ED measurement type/class may be defined according to aspecific ED threshold. Alternatively, when Tx powers or LBT BWs of theUE are equal and the sizes of LBT beams (e.g., widths of the beams) aredifferent so that different ED measurement types/classes are defined,different ED thresholds may be configured according to the EDmeasurement types/classes.

The UE may previously report the information about the ED capabilitythereof to the BS, and the BS may indicate the ED measurement type/classand the ED threshold of the D-LBT together with the UL schedulinginformation based on the information about the ED capability of the UE.

The above-described ED measurement-related requirements of the UE may bedefined as a shape of a beam pattern when the UE performs ULtransmission through antennas thereof. For example, when UL transmissionin a space of a virtual sphere shape occupies an area A in a virtualsphere and D-LBT may be performed through an area B including the areaA, the ED measurement type/class may be defined based on the size of anarea B-A (i.e., the difference between the area B and the area A).

As another example, an ED threshold type 1 (or ED threshold class 1) forthe same specific ED threshold may be a wide beam in which the beamwidth of an LBT beam (e.g., Rx beam pattern) is wider than the beamwidth of a Tx beam. In this case, the wide beam may mean a beam in whichthe width of a main lobe in a beam pattern is relatively large.

An ED threshold type 2 (or ED threshold class 2) may be defined in theED measurement requirements as a relatively narrow beam in which thedifference between the beam width of an LBT beam (e.g., Rx beam pattern)and the beam width of a Tx beam is not large. Here, the narrow beam maymean a beam in which the width of a main lobe in a beam pattern isrelatively small and the difference between the width of the main lobeof the Tx beam and the width of a side lobe in the beam pattern is notlarge (e.g., difference equal to or less than a certain value). Forexample, when beam correspondence is established, a Tx beam directioncorresponding to a CSI-RS Rx beam may be relatively narrow relative to aTx beam direction corresponding to an SSB Rx beam. In other words, whenbeam correspondence is established, the Tx beam direction correspondingto the CSI-RS Rx beam may be a relatively wide beam compared to the Txbeam direction corresponding to the SSB Rx beam.

According to the capability of the UE, some UEs may support both the EDthreshold type 1 and the ED threshold type 2 (or ED threshold class 1and ED threshold class 2) and other UEs may support only ED measurementof a specific type/class.

The BS may configure an LBT beam and a specific RS as a spatial relationbased on the information about capability for the ED measurement type(or class) reported by the UE and indicate to/configure for the UE theED measurement type (or class) and the ED threshold of D-LBT during ULscheduling.

For example, the case in which a DL RS having a spatial relation with anLBT beam is a CSI-RS may be configured as an ED measurement type 1 (orclass 1), and the case in which the DL RS having a spatial relation withthe LBT beam is an SSB may be configured as ED measurement type 2 (orclass 2). In addition, the case in which the DL RS having a spatialrelation with the LBT beam is an SRS may be configured as an EDmeasurement type 3 (or class 3).

After configuring the ED measurement type (or class) as described above,when the BS performs UL scheduling for the UE, the BS may indicate adirection of the LBT beam in which D-LBT for each UL channel/signal isto be performed and the ED measurement type (or class). In addition, theED threshold may be differently configured for/indicated to the UEaccording to a DL signal which is in a spatial relation with a ULsignal/channel to be transmitted by the UE.

[Proposed Method #2]

The BS and the UE may configure an ED measurement type (or class) and anED threshold in consideration of directions and an interference range ofTx beam(s) to be transmitted within a COT.

1. Embodiment #2-1

An ED measurement type (or class) and an ED threshold covering a totalinterference range of one or more Tx beams to be transmitted throughspatial division multiplexing (SDM) within the COT may be configured.

(1) The ED threshold may be configured/indicated based on a Tx beamhaving {largest effective isotropic radiated power (EIRP), average EIRP,or minimum EIRP} among one or more Tx beams to be transmitted throughSDM within the COT.

(2) D-LBT may be simultaneously performed on one or more Tx beams usinga single LBT beam that covers an interference range of one or more Txbeams to be transmitted through SDM within the COT. In this case, thesingle LBT beam may be a relatively wide beam.

For example, referring to FIG. 23(a), when four Tx beams (Tx Beam 1 toTx Beam 4) are multiplexed using SDM, the BS or the UE may perform D-LBTusing an LBT beam, which is a single LBT beam that covers all of thefour Tx beams Tx Beam 1 to Tx Beam 4. For example, “the single LBT beamcovers all of the four Tx beams” may mean that an LBT area through thesingle LBT beam includes a total interference range in which the four Txbeams affect interference.

In addition, upon succeeding in D-LBT using the LBT beam, the BS or theUE may perform DL/UL transmission through Tx Beam 1 to Tx Beam 4 thatare multiplexed using SDM. In this case, each DL/UL transmission may bescheduled through each of Tx Beam 1 to Tx Beam 4, and the scheduledDL/UL signals/channels may be transmitted through SDM. On the otherhand, DL/UL transmission may be performed over adjacent Tx beams. Forexample, if DL/UL signals/channels are scheduled over Tx Beam 1 and TxBeam 2, the DL/UL signals/channels scheduled through Tx Beam 1 and TxBeam 2 may be transmitted through SDM.

(3) D-LBT may be sequentially performed using multiple LBT beams thatcover an interference range of one or more Tx beams to be transmittedthrough SDM within the COT. According to the success or failure of D-LBTof the multiple LBT beams, Tx beams in a beam direction capable of beingcontinuously transmitted without a gap may be transmitted through SDMamong beam directions in which D-LBT is successful. Each of the multipleLBT beams may be a relatively narrow beam.

For example, referring to FIG. 23(b), when four Tx beams (Tx Beam 1 toTx Beam 4) are multiplexed using SDM, the BS or the UE may perform D-LBTon LBT Beam 1 to LBT Beam 4 that cover 4 Tx beams, respectively. Here,LBT Beam 1 is a beam that covers Tx Beam 1, and LBT Beam 2 is a beamthat covers Tx Beam 2. In addition, LBT Beam 3 is a beam that covers TxBeam 3, and LBT Beam 4 is a beam that covers Tx Beam 4. For example, anLBT area of LBT Beam 1 includes an interference range of Tx Beam 1 andmay be greater than or equal to the interference range of Tx Beam 1corresponding to the LBT area of LBT Beam 1. In other words, an LBT areaof each LBT beam should necessarily include an interference range of aTx beam corresponding to each LBT beam and may be greater than or equalto the interference range of the Tx beam. That is, the LBT area of eachLBT beam may be greater than or equal to the interference range of a Txbeam corresponding to each LBT beam and may include all of theinterference range of the corresponding Tx beam.

The BS or the UE may perform D-LBT simultaneously or sequentially oneach of LBT Beam 1 to LBT Beam 4. For example, the BS or the UE maysequentially perform D-LBT on each LBT beam from D-LBT using LBT Beam 1to D-LBT using LBT Beam 4 or simultaneously perform D-LBT on LBT Beam 1to LBT Beam 4.

In this case, among LBT beams that have succeeded in D-LBT, Tx beams maybe used for DL/UL transmission through SDM in a Tx beam directioncapable of being continuously transmitted without a gap.

For example, if D-LBT for LBT Beam 2 fails and D-LBT for LBT Beams 1, 3,and 4 are successful, Tx Beam 3 and Tx Beam 4 may be used for DL/ULtransmission through SDM. For example, each DL/UL transmission may bescheduled through each of Tx Beam 3 and Tx Beam 4, and the scheduledDL/UL signals/channels may be transmitted through SDM. On the otherhand, transmission of one DL/UL signal/channel may be performed over TxBeam 3 and Tx Beam 4. In other words, one DL/UL signal/channel may bescheduled to be transmitted through Tx Beam 3 and Tx Beam 4, and DL/ULsignals/channels scheduled over Tx Beam 3 and Tx Beam 4 may betransmitted through SDM.

(4) In a situation in which multiple TRPs are configured, if differentTRPs schedule UL signals/channels in the same symbol for the UE, so thatthe UE should simultaneously transmit the UL signals/channels todifferent TRPs in the same symbol (e.g., if the UE should simultaneouslytransmit the UL signals/channels through SDM to different TRPs), Txpower is divided by the number of Tx beams used by the UE forsimultaneous transmission, so that Tx power allocated to each Tx beammay be reduced. Accordingly, an ED threshold for an LBT beam in adirection corresponding to each Tx beam may be configured to beincreased based on the reduced Tx power applied to each Tx beam. Forexample, the ED threshold for the LBT beam may be increased as much asthe reduced Tx power applied to each Tx beam or may be increased tocorrespond to the reduce Tx power or may be increased to be inverselyproportional to the reduced Tx power.

In this case, if the UE has multiple panels for a plurality of Tx beams(or a plurality of LBT beams), the UE may perform D-LBT according to anLBT beam indicated for each panel. On the other hand, the method (4) ofEmbodiment #2-1 may be limitedly applied only to the UE.

2. Embodiment #2-2

An ED measurement type (or class) and an ED threshold that cover a totalinterference range of one or more Tx beams to be transmitted through TDMwithin the COT may be configured.

(1) The ED threshold may be configured/indicated based on {largest EIRP,average EIRP, minimum EIRP, Tx beam to be transmitted first, or Tx beamhaving longest Tx duration} among one or more Tx beams to be transmittedthrough TDM within the COT.

(2) D-LBT may be simultaneously performed on one or more Tx beams usinga single LBT beam that covers an interference range of one or more Txbeams to be transmitted through TDM within the COT. The single LBT beammay be a relatively wide beam. DL/UL signals or channels may besequentially transmitted for each Tx beam.

For example, referring to FIG. 24(a), when four Tx beams (Tx Beam 1 toTx Beam 4) are multiplexed using TDM, the BS or the UE may perform D-LBTusing an LBT beam, which is a single LBT beam that covers all of thefour Tx beams Tx Beam 1 to Tx Beam 4. For example, “the single LBT beamcovers all of the four Tx beams” may mean that an LBT area through thesingle LBT beam includes a total interference range in which the four Txbeams affect interference.

In addition, upon succeeding in D-LBT using the LBT beam, the BS or theUE may perform DL/UL transmission through Tx Beam 1 to Tx Beam 4 thatare multiplexed using TDM. In this case, each DL/UL transmission may bescheduled through each of Tx Beam 1 to Tx Beam 4, and the scheduledDL/UL signals/channels may be multiplexed using TDM and DL/ULsignals/channels from a DL/UL signal/channel for Tx Beam 1 to a DL/ULsignal/channel for Tx Beam 4 may be sequentially transmitted. On theother hand, DL/UL transmission may be performed over adjacent Tx beams.For example, if a first DL/UL signal/channel is scheduled over Tx Beam 1and Tx Beam 2 and a second DL/UL signal/channel is scheduled over TxBeam 3 and Tx Beam 4, the first DL/UL signal/channel and the secondDL/UL signal/channel may be sequentially transmitted through TDM.

In the case of FIG. 24(a), since a COT has already been obtained bydetermining that a channel is idle through an LBT beam when Tx beamswitching is performed like the case in which a Tx beam is switched fromTx Beam 1 to Tx Beam 2 or from Tx Beam 1 and Tx Beam 2 to Tx Beam 3 andTx Beam 4, the DL/UL signals/channels may be transmitted by performingTx beam switching without performing additional LBT (i.e., based on ano-LBT mode).

(3) D-LBT may be sequentially performed using multiple LBT beams thatcover an interference range of one or more Tx beams to be transmittedthrough TDM within the COT. The DL/UL signals/channels may besequentially transmitted through Tx beams corresponding to LBT beams forwhich D-LBT is successful. Each of the multiple LBT beams may be arelatively narrow beam.

For example, referring to FIG. 24(b), when four Tx beams (Tx Beam 1 toTx Beam 4) are multiplexed using TDM, the BS or the UE may perform D-LBTon LBT Beam 1 to LBT Beam 4 that cover 4 Tx beams, respectively. Here,LBT Beam 1 is a beam that covers Tx Beam 1, and LBT Beam 2 is a beamthat covers Tx Beam 2. In addition, LBT Beam 3 is a beam that covers TxBeam 3, and LBT Beam 4 is a beam that covers Tx Beam 4. For example, anLBT area of LBT Beam 1 includes an interference range of Tx Beam 1 andmay be greater than or equal to the interference range of Tx Beam 1corresponding to the LBT area of LBT Beam 1. In other words, an LBT areaof each LBT beam should necessarily include an interference range of aTx beam corresponding to each LBT beam and may be greater than or equalto the interference range of the Tx beam. That is, the LBT area of eachLBT beam may be greater than or equal to the interference range of a Txbeam corresponding to each LBT beam and may include all of theinterference range of the corresponding Tx beam.

The BS or the UE may perform D-LBT simultaneously or sequentially oneach of LBT Beam 1 to LBT Beam 4. For example, the BS or the UE maysequentially perform D-LBT on each LBT beam from D-LBT using LBT Beam 1to D-LBT using LBT Beam 4 or simultaneously perform D-LBT on LBT Beam 1to LBT Beam 4.

In this case, DL/UL signal/channels may be sequentially transmittedthrough respective Tx beams. If D-LBT for partial LBT beams issuccessful in performing D-LBT through LBT Beam 1 to LBT Beam 4, onlyDL/UL signals/channels for Tx beams corresponding to the LBT beams forwhich D-LBT is successful may be transmitted.

For example, if D-LBT for LBT Beam 2 fails and D-LBT for LBT Beams 1, 3,and 4 is successful, transmission of a DL/UL signal/channel scheduledfor Tx Beam 2 may be dropped, and only DL/UL signals/channels scheduledfor Tx Beams 1, 3, and 4 may be transmitted.

As another example, the DL/UL signal may be scheduled across twodifferent Tx beams. For example, a first DL/UL signal/channel may bescheduled across Tx Beam 1 and Tx Beam 2, and a second DL/ULsignal/channel may be scheduled across Tx Beam 3 and Tx Beam 4. In thiscase, if D-LBT in all LBT beams is successful, the first DL/ULsignal/channel and the second DL/UL signal/channel may be multiplexedusing TDM and then sequentially transmitted.

Meanwhile, if D-LBT for partial LBT beams fails, DL/UL signals/channelsscheduled for Tx beams corresponding to the partial LBT beams may not betransmitted. For example, if D-LBT for LBT Beams 1, 3, and 4 aresuccessful and D-LBT for LBT Beam 2 fails, the first DL/ULsignal/channel may be dropped, and only the second DL/UL signal may betransmitted.

In the case of FIG. 24(b), since a COT has already been obtained bydetermining that a channel is idle through LBT Beam 1 to LBT Beam 4 whenTx beam switching is performed like the case in which a Tx beam isswitched from Tx Beam 1 to Tx Beam 2 or from Tx Beam 1 and Tx Beam 2 toTx Beam 3 and Tx Beam 4, the DL/UL signals/channels may be transmittedby performing Tx beam switching without performing additional LBT (i.e.,based on a no-LBT mode).

When DL/UL signals/channels are sequentially transmitted through TDMacross different Tx beams within the COT obtained after succeeding inD-LBT in (2) and (3) of Embodiments #2-2 described above, if a timerequired for switching between two different Tx beams is equal to orless than a specific time T, non-random backoff-based LBT, i.e., Cat-2LBT or Cat-1 LBT, may be performed and then the DL/UL signals/channelsmay be transmitted through a switched Tx beam. However, if the switchingtime between the two different Tx beams is greater than T, since the COTmay not be maintained, random backoff-based Cat-3 LBT or Cat-4 LBTshould be performed again.

FIG. 25 illustrates that non-random backoff-based Cat-2 LBT or Cat-1 LBTis performed when a Tx beam is switched in the same situation as in FIG.24 described above.

In the case of FIGS. 25(a) and 25(b), although it has been confirmedthat a channel is idle through an LBT beam (or LBT Beam 1 to LBT Beam 4)in a process of LBT #1 when Tx beam switching is performed as in thecase in which a Tx beam is switched from Tx Beam 1 to Tx Beam 2 or fromTx Beam 1 and Tx Beam 2 to Tx Beam 3 and Tx Beam 4, since other noisemight occur while the Tx beam is switched as time elapses, non-randombackoff-based Cat-2 LBT or Cat-1 LBT may be performed (LBT #2) beforethe Tx beam is switched using an LBT beam corresponding to the Tx beamafter switching.

For example, when the Tx beam is switched from Tx Beam 1 to Tx Beam 2,if the time required for switching from Tx Beam 1 to Tx Beam 2 is equalto or less than T, non-random backoff-based Cat-2 LBT or Cat-1 LBT maybe performed using LBT Beam 2, and the DL/UL signal/channel may betransmitted through Tx Beam 2. As another example, when the Tx beam isswitched from Tx Beam 1 and Tx Beam 2 to Tx Beam 3 and Tx Beam 4, if thetime consumed for switching from Tx Beam 1 and Tx Beam 2 to Tx Beam 3and Tx Beam 4 is equal to or less than T, non-random backoff-based Cat-2LBT or Cat-1 LBT may be performed using LBT Beam 3 and LBT Beam 4, andthe DL/UL signal/channel may be transmitted through Tx Beam 3 and TxBeam 4.

In the above example, if the time consumed for switching from Tx Beam 1to Tx Beam 2 or from Tx Beam 1 and Tx Beam 2 to Tx Beam 3 and Tx Beam 4exceeds T, random backoff-based Cat-3 LBT or Cat-4 LBT should beperformed using LBT Beam 2 or LBT Beam 3 and LBT Beam 4 to transmit theDL/UL signal/channel.

FIG. 25(a) illustrates that non-random backoff-based Cat-2 LBT or Cat-1LBT is performed using LBT Beam 1 before the DL/UL signal/channel istransmitted through Tx Beam 1. However, since this transmissioncorresponds to transmission performed immediately after it is confirmedthat the channel is idle through an LBT beam (or LBT Beam 1 to LBT Beam4), non-random backoff-based Cat-2 LBT or Cat-1 LBT using LBT Beam 1 maybe omitted. That is, after performing random backoff-based Cat-3 LBT orCat-4 LBT through the LBT beam (or LBT Beam 1 to LBT Beam 4), non-randombackoff-based Cat-2 LBT or Cat-1 LBT for first DL/UL signal/channeltransmission may be omitted.

Meanwhile, whether the Tx beam is switched based on a no-LBT modewithout additional LBT as illustrated in FIG. 24 or whether the Tx beamis switched after performing non-random backoff-based Cat-2 LBT or Cat-1LBT as illustrated in FIG. 25 may follow the regulations of eachcountry/region.

(1) of Embodiment #2-2 may be limitedly used only when other RATs do notexist in the vicinity of the UE or the BS. The COT length in (1) ofEmbodiment #2-2 may be constrained to be relatively shorter than in (2)of Embodiment #2-2.

The SDM/TDM transmission method and the ED threshold configurationmethod proposed in [Proposed Method #2] may be applicable to both the BSand the UE except for (4) of Embodiment #2-1. Even the ED measurementtype indication may be limitedly applied to the case in which the BSindicates the type to the UE.

Hereinafter, [Proposed Method #2] will be described in detail.

A DL/UL signal/channel may be transmitted in an area in which D-LBT issuccessful during a COT acquired by success of D-LBT in a specific LBTbeam direction. In addition, Tx beams in different directions may bemultiplexed using SDM or TDM within the acquired COT.

On the other hand, transmission of the DL/UL signal/channel may beallowed only when directions and an interference range of Tx beams indifferent directions are all included in an area in which an LBT beamperforms CCA (i.e., LBT). If it is desired to transmit the DL/ULsignal/channel through a Tx beam in an area other than the area in whichthe LBT beams has performed CCA (i.e., LBT), D-LBT should be performedagain in a direction including the corresponding area.

In other words, in order to transmit the DL/UL signal/channel byperforming SDM or TDM on a plurality of Tx beams within the COT, an LBTbeam should be configured/indicated in consideration of the directionsand the interference range of the multiplexed Tx beams, and D-LBT shouldbe performed using the corresponding LBT beam.

Therefore, the BS or the UE may configure an ED measurement type (orclass) and an ED threshold in consideration of the directions and theinterference range of one or more Tx beams to be transmitted within theCOT.

First, as a method of configuring the ED threshold of an LBT beam, theED threshold may be configured for/indicated to the UE based on one of{largest EIRP, average EIRP, or minimum EIRP} among one or more Tx beamsto be transmitted through SDM within the COT as in Embodiment #2-1(a).

According to a conservative standard, since an area in which a Tx beamwith the largest EIRP causes interference may be relatively large, ifthe ED threshold is configured based on the Tx beam with the largestEIRP power, the ED threshold may be configured to be relatively low.Alternatively, in order to slightly increase a channel accessopportunity, the ED threshold may be configured based on a Tx beamhaving the lowest EIRP. Alternatively, the ED threshold may beconfigured based on an average EIRP of Tx beams to be multiplexed usingSDM.

D-LBT may be simultaneously performed on one or more Tx beams using asingle LBT beam that covers an interference range of one or more Txbeams to be transmitted through SDM in the COT. In this case, the singleLBT beam may be a relatively wide beam.

The direction of the LBT beam and an Rx beam pattern may be configuredfor/indicated to the UE supporting ED measurement type 1 as a spatialrelation between the LBT beam and the SSB as in the example of [ProposedMethod #1].

Alternatively, D-LBT may be sequentially performed using multiple LBTbeams that cover the interference range of one or more Tx beams to betransmitted through SDM in the COT. Each of the multiple LBT beams maybe a relatively narrow beam.

In this case, as in the example of [Proposed Method #1], the spatialrelation between the LBT beam and the CSI-RS may be configuredfor/indicated to the UE supporting ED measurement type 2. Here, the Txbeams may be multiplexed using SDM only in directions of Tx beams whichmay be continuously transmitted without a gap among Tx beamscorresponding to directions of LBT beams that have succeeded in D-LBTaccording to the success or failure of D-LBT of multiple LBT beams.

For example, if D-LBT based on LBT Beam 1 and LBT Beams 3 and 4 issuccessful and D-LBT based on LBT Beam 2 fails as a result ofsequentially performing D-LBT through LBT Beams 1, 2, 3, and 4, only Txbeams corresponding to LBT Beams 3 and 4 may be used through SDM totransmit the DL/UL signal/channel.

Characteristically, as in (4) of Embodiment #2-1, in a situation inwhich multiple TRPs are configured, if simultaneous transmission (e.g.,SDM) is scheduled for the UE in the same symbol through respective ULgrants from different TRPs, so that UL transmission should be performedin different TRP directions, Tx power is divided by the number ofsimultaneously transmitted Tx beams. Therefore, an ED threshold may beconfigured to be increased based on the reduced Tx power applied to eachTx beam. For example, an ED threshold for an LBT beam may be increasedas much as the reduced Tx power applied to each Tx beam or may beincreased to correspond to the reduced Tx beam or may be increased to beinversely proportional to the reduced Tx power. Therethrough, thechannel access opportunity of the UE may be increased. In this case, ifthe UE has multiple panels for a plurality of Tx beams (or a pluralityof LBT beams), D-LBT may be performed according to an LBT beam indicatedfor each panel.

As described in (1) of Embodiment #2-2, even when transmission isperformed through TDM in a plurality of Tx beam directions within a COT,the ED threshold may be configured/indicated based on one of {largestEIRP, average EIRP, minimum EIRP, Tx beam to be transmitted first, or Txbeam having longest Tx duration} among one or more Tx beams to betransmitted through TDM within the COT.

As described in (2) of Embodiment #2-2, D-LBT may be simultaneouslyperformed on one or more Tx beams using a single LBT beam that covers aninterference range of one or more Tx beams to be transmitted through TDMwithin the COT. In this case, the single LBT beam may be a relativelywide beam.

The direction of the LBT beam and an Rx beam pattern may be configuredfor/indicated to the UE supporting ED measurement type 1 as a spatialrelation between the LBT beam and the SSB as in the example of [ProposedMethod #1].

Alternatively, as described in (3) of Embodiment #2-2, D-LBT may besequentially performed using multiple LBT beams that cover theinterference range of one or more Tx beams to be transmitted through TDMwithin the COT. Each of the multiple LBT beams may be a relativelynarrow beam.

Therefore, in this case, as in the example of [Proposed Method #1], thespatial relation between the LBT beam and the CSI-RS may be configuredfor/indicated to the UE supporting ED measurement type 2.

As in (2) of Embodiment #2-1 and (2) of Embodiment #2-2, performingD-LBT using a single LBT beam that covers the interference range of oneor more Tx beams has an advantage of being not significantly affected bythe capabilities of the UE or the BS.

In other words, when performing D-LBT using a single LBT beam thatcovers the interference range of one or more Tx beams, even when thecapability of the UE or the BS is low as in the case in which the numberof panels with which the UE or BS performs LBT is 1 or the number ofpanels with which the UE or the BS is capable of simultaneouslyperforming LBT is 1, construction costs or implementation issues (orimplementation difficulty) of the UE or the BS may not be high becausethe UE or the BS may perform D-LBT for one or more Tx beams.

Further, as in (3) of Embodiment #2-1 and (3) of Embodiment #2-2,performing D-LBT using multiple LBT beams each covering the interferencerange of one or more Tx beams may increase the transmission efficiencyof the UE or the BS.

For example, when transmission of the DL/UL signal/channel is scheduledone by one for each of Tx Beam 1 to Tx Beam 4, if D-LBT for LBT Beam 2corresponding to Tx Beam 2 fails and D-LBT for LBT Beam 1, LBT Beam 3,and LBT Beam 4 corresponding to Tx Beam 1, Tx Beam 3, and Tx Beam 4 issuccessful, only transmission of the DL/UL signal/channel scheduled forTx Beam 2 may be dropped and DL/UL signals/channels scheduled for TxBeam 1, Tx Beam 3, and Tx Beam 4 may be transmitted, so thattransmission efficiency and resource utilization efficiency may beincreased.

[Proposed Method #3]

When the BS or the UE performs LBT always in units of an LBT bandwidthbefore transmission, LBT bandwidth (hereinafter referred to as ‘LBT-BW’)considering the relationship with a BWP/CC may be configured.

1. Embodiment #3-1

An LBT-BW area associated with a corresponding BWP/CC for each BWP/CCmay be configured. That is, the LBT-BW area used for LBT forcorresponding BWP/CC transmission may be configured. For example, astarting RB and a bandwidth (BW) of the LBT-BW area may be configured.Alternatively, a starting RB and an ending RB of the LBT-BW area may beconfigured. Alternatively, a starting RB of the LBT area and the numberof RBs of the LBT-BW area may be configured.

2. Embodiment #3-2

Without separate association with a BWP/CC, each LBT-BW or LBT-BW setmay be configured. For example, if a starting RB and a BW of an LBT-BWarea, and the number N of LBT-BWs are configured, N (consecutive)LBT-BWs having a BW size from the starting RB may be configured. In thiscase, an ending RB or the number of RBs may be configured instead of theBW. For example, the starting RB and the ending RB of the LBT-BW area,and the number N of LBT-BWs may be configured, or the starting RB of theLBT-BW area, the number of RBs, and the number N of LBT-BWs may beconfigured.

3. Embodiment #3-3

Only a minimum LBT-BW (e.g., min-BW) value may be configured and anactual LBT-BW may be determined according to the relationship with aBWP/CC size.

For example, for a BWP/CC smaller than min-BW, the actual LBT-BW may beconfigured as min-BW (i.e., LBT-BW=min-BW). For a BWP/CC greater thanmin-BW, the LBT-BW may be configured as the BWP/CC (i.e.,LBT-BW=BWP/CC).

4. Embodiment #3-4

The BS may configure an LBT BW index for each CC preconfigured ascarrier aggregation (CA) with respect to the UE for which CCs of variousBW sizes are configured as CA. The BS may perform LBT according to anLBT BW index indicated during UL scheduling.

The relationship between the BWP/CC and the LBT-BW may have a structurein which a plurality of (narrow) LBT-BWs is included in one (wide)BWP/CC as in legacy Rel-16 NR-U or, conversely, a structure in which one(wide) BWP/CC or a plurality of (wide) BWPs/CCs is included in a singleLBT-BW. One BWP/CC may be configured to be confined in only one LBT-BW.That is, a configuration in which one BWP/CC spans a plurality ofLBT-BWs may be excluded.

Hereinafter, [Proposed method #3] will be described in detail.

In Rel-16 NR-U, a unit LBT-BW always using 20 MHz as a basic unit of LBThas been considered in consideration of coexistence of requirements suchas a nominal channel BW defined in a 5-GHz band regulation (e.g., ETSIEN 302 893) with an incumbent system (e.g., 802.11-series Wi-Fi system).

However, in FR4 (e.g., a band of 60 GHz) being newly considered inRel-17, the definition of the unit LBT-BW to be performed before the BSand the UE perform transmission is ambiguous upon considering regulation(e.g., ETSI EN 302 567) and the incumbent system (e.g., WiGig).Therefore, it is necessary to define an LBT-BW in which the BS and theUE may efficiently perform LBT prior to transmission and transmit andreceive DL/UL signals/channels in the FR4 band.

For example, if the LBT-BW is not defined, the BS or the UE may performLBT on a total channel BW or a BWP BW for transmission or perform LBT asmuch as a transmission BW for transmission (e.g., from the lowest RB tothe highest RB used for transmission).

In the case of multi-carrier transmission for which intra-band CA isconfigured, multiple LBT operations may be separately performed for eachchannel BW. Alternatively, LBT may be performed only as much as atransmission BW for each CC. Therefore, it is necessary to configure theLBT-BW in consideration of the relationship between the LBT-BW and theBWP/CC. Therethrough, a problem of inequality of LBT opportunities thatmay occur when the BS and the UE perform LBT based on an unnecessarilywide BW or when the UE and BS perform LBT using BWs of different sizesmay be eliminated, and LBT and transmission/reception may be efficientlyperformed.

Embodiment #3-1 is a method of configuring the LBT-BW area associatedwith a corresponding BWP/CC for each BWP/CC, i.e., a method ofconfiguring the LBT-BW area used for LBT for corresponding BWP/CCtransmission. For example, a starting RB and BW size of an LBT-BWassociated with a specific BWP/CC may be configured.

Alternatively, a starting RB and an ending RB of an LBT-BW associatedwith a specific BWP/CC may be configured. Alternatively, the starting RBand the number of RBs of the LBT-BW associated with a specific BWP/CCmay be configured.

Embodiment #3-2 is a method of configuring each LBT-BW or LBT-BW setwithout separate association with a BWP/CC. For example, if a startingRB and a BW of an LBT-BW, and the number of LBT-BWs are configured, N(consecutive) LBT-BWs having a BW size from the starting RB may beconfigured. In this case, an ending RB or the number of RBs may beconfigured instead of the BW. For example, a starting RB and an endingRB of the LBT-BW, and the number of LBT-BWs may be configured or thestarting RB of the LBT-BW, the number of RBs of the LBT-BW, and thenumber N of LBT-BWs may be configured.

Embodiment #3-3 may configure only a minimum LBT-BW (e.g., min-BW) valueand determine an actual LBT-BW according to the relationship with aBWP/CC size. For example, for a BWP/CC smaller than min-BW, the actualLBT-BW may be configured as min-BW (i.e., LBT-BW=min-BW). For a BWP/CCgreater than min-BW, LBT-BW may be configured as the correspondingBWP/CC (i.e., LBT-BW=BWP/CC).

For example, if LBT-BW=max (min-BW, BWP BW, or CC BW), the size of theLBT-BW may be determined as follows.

1) For BWP/CC>min-BW, LBT-BW=BWP/CC

2) For BWP/CC<min-BW, LBT-BW=min-BW

3) For BWP/CC=min-BW, LBT-BW=BWP/CC=min-BW

Here, in the case of 2), a starting position or a center position of themin-BW may be configured to be equal to a starting position or a centerposition of the BWP/CC. Alternatively, the position of the LBT-BW may beconfigured by setting a relative value of the starting position or thecenter position of the min-BW from the starting position or the centerposition of the BWP/CC.

As an example of Embodiment #3-4, if three CCs of {CC1 with a size of400M, CC2 with a size of 200M, CC3 with a size of 200M} are configuredas CA for the UE, and if LBT-BW indexes corresponding to CC1, CC2, andCC3 are configured as {0, 1, 1}, respectively, since only {CC1} isincluded in LBT-BW index 0, LBT may be performed based on an LBT-BW witha size of 400 MHz. In addition, since LBT BW index 1 includes {CC2,CC3}, LBT may be performed based on an LBT-BW with a size of 400 MHzobtained by adding CC2 and CC3.

As another example, if LBT BW index={0, 0, 1}, since {CC1, CC2} areincluded in LBT-BW index 0, LBT based on a size of 600 MHz may beperformed. Since only {CC3} is included in LBT-BW index 1, LBT based ona size of 200 MMHz may be performed.

As another example, it may be regulated that a starting RB and an endingRB are configured for each LBT-BW index and one CC or a plurality of CCsmay be completely included within an RB range configured for each LBT-BWindex. In other words, the starting RB and/or the ending RB may bedefined to always be configured at the boundary of a CC BW. That is, itmay be regulated that the starting RB and/or the ending RB is notconfigured to overlap only a part of a CC BW within the CC BW. As anexample different from the above example, the starting RB and the numberof RBs may be configured for each LBT-BW index.

One BWP/CC is configured to be confined only in one LBT-BW. Accordingly,a configuration in which one BWP/CC spans a plurality of LBT-BWs isexcluded. Even if the LBT-BW configured for the UE is larger than thesize of the BWP/CC, LBT should always be performed with the LBT-BW sizethrough CA, etc.

An ED threshold used to perform LBT may be expressed as a function ofthe size of an output power of the UE or BS and the size of an operatingchannel BW. The relationship between these two factors and the EDthreshold may be expressed as in [Equation 1].

$\begin{matrix}{{EDT} = {{{- 80}{dBm}} + {10*\log 10\left( \frac{P\max}{Pout} \right)} + {10*\log 10\left( {{Operating}{Channel}{BW}{in}{MHz}} \right)}}} & \left\lbrack {{Equation}1} \right\rbrack\end{matrix}$

Here, the operating channel BW may be the size of a BW of LBT performedby the UE or the BS or mean the BW size of a BWP or the transmission BWwith which transmission is actually performed. However, in a 60-GHzband, since D-LBT that performs LBT only in a specific Tx direction as atarget, rather than O-LBT performed in a 5-GHz band, is considered, theED threshold may be differently configured according to the relationshipbetween a sensing beam and a Tx beam (e.g., beam correspondence).

The capability of the UE for the above-described beam correspondence isdefined in Section 6.6 of TS 38.101-2 and the BS may differentlyconfigure the ED threshold used to perform D-LBT according to the beamcorrespondence capability of the UE as follows.

1) A UE supporting beamCorrespondenceWithoutUL-BeamSweeping may wellestablish beam correspondence even without BM such as UL beam sweepingand UL beam indication of a network. In this case, the UE should satisfyrequirements such as minimum peak EIRP and spherical coverage evenwithout BM.

2) A UE that does not support beamCorrespondenceWithoutUL-BeamSweepingmay satisfy requirements such as minimum peak EIRP and sphericalcoverage through a BM procedure. In addition, the UE may satisfy arelaxed requirement of about 3 dB even without the BM procedure.

[Proposed Method #4]

The UE may adjust the ED threshold used to perform LBT according towhether the UE supports beam correspondence (BC) and whether the BMprocedure is performed.

1. Embodiment #4-1

In the case of a UE supporting beamCorrespondenceWithoutUL-BeamSweeping,the ED threshold may be calculated in consideration of only the outputpower and the operating channel BW.

2. Embodiment #4-2

In the case of a UE that does not supportbeamCorrespondenceWithoutUL-BeamSweeping, the ED threshold may becalculated using at least one of the following methods.

(1) An additional penalty value, X dB, explicitly configured/indicatedby the BS may be applied to the ED threshold calculated based on theoutput power and the operating channel BW according to [Equation 1]. Forexample, the ED threshold may be decreased by applying the penaltyvalue.

(2) If there is no penalty of X dB explicitly configured by the BS, X=3dB may be applied as a default.

If an additional configuration is received from the BS, the same EDthreshold as in Embodiment #4-1 in the case of having the BC capabilitymay be used without penalty.

(3) The penalty may be implicitly applied depending on whether an SRSused for BM is configured for the UE.

In the case in which the SRS used for BM is not configured, a penalty ofa 3 dB may be added to the ED threshold calculated based on the outputpower and the operating channel BW according to [Equation 1], so thatLBT may be performed using a lower ED threshold.

Alternatively, when only an SRS in which repetition is set to ‘OFF’ isconfigured or after the configured SRS is transmitted at least N times(assuming that a BM procedure has been performed), the same ED thresholdas in Embodiment #4-1 with the BC-related capability may be used.

(4) Alternatively, even if the UE does not supportbeamCorrespondenceWithoutUL-BeamSweeping, X=0 dB may be applied as adefault X value for calculating the ED threshold (until a penalty of XdB is explicitly configured by the BS). This is because a specialproblem does not occur even if the ED threshold is not differentlyconfigured depending on whether beamCorrespondenceWithoutUL-BeamSweepingis supported according to the number of beams and the number of UEsoperated in a cell.

[Proposed method #4] will be described in detail.

As described above, when BC is established between DL beams and ULbeams, either a procedure for determining a DL beam pair or a BMprocedure for determining a UL beam pair may be omitted. Establishing BCmay mean that it may be assumed that a BS Tx beam and a BS Rx beamcoincide and a UE Tx beam and a UE Rx beam coincide in communicationbetween the BS and the UE. Here, the BS Tx beam and the BS Rx beam maymean a DL Tx beam and a DL Rx beam, respectively, and the UE Tx beam andthe UE Rx beam may mean a UL Tx beam and a UL Rx beam, respectively.

In the case of D-LBT performed by a Tx end, energy in an area that issubjected to interference when a Tx beam is transmitted (e.g., an areaequal to or greater than an area in which the Tx beam affectsinterference) may be measured through an Rx beam in consideration of aTx beam direction in which the BS or the UE desires to performtransmission. Then, whether a channel is idle or busy may be determinedby comparing the measured energy with the ED threshold. In addition,whether to perform transmission may be determined based on determinationof whether the channel is idle or busy. Therefore, when performing LBTthrough the Rx beam, the ED threshold may be adjusted according to BCand reflected in determining whether the channel is idle or busy.

ED threshold adjustment based on BC may be changed depending on whetherthe UE supports beamCorrespondenceWithoutUL-BeamSweeping and whether aBM procedure is performed. In the case of the UE supportingbeamCorrespondenceWithoutUL-BeamSweeping, the ED threshold may becalculated by [Equation 1] considering only the output power and theoperating channel BW without a separate penalty and may be applied toLBT.

In the case of the UE that does not supportbeamCorrespondenceWithoutUL-BeamSweeping, an additional penalty of X dBexplicitly configured/indicated by the BS may be applied to the EDthreshold calculated using the output power and operating channel BW of[Equation 1]. For example, the ED threshold may be decreased by applyingthe penalty value. Alternatively, if there is no penalty value of X dBconfigured by the BS, X=3 dB may be applied as a default. However, if anadditional configuration is received from the BS, the same ED thresholdvalue as in Embodiment #4-1 in the case of having the BC capability maybe used without penalty.

As another example, the penalty may be implicitly applied according towhether the SRS used for BM is configured for the UE.

When the SRS used for BM is not configured, a penalty of 3 dB may alwaysbe applied to the ED threshold calculated based on the output power andoperating channel BW of [Equation 1], so that LBT may be performed usingthe lower obtained ED threshold.

If only the SRS used for BM is configured or after the configured SRS istransmitted at least N times (assuming that the BM procedure has beenperformed), the same ED threshold as in Embodiment #4-1 with theBC-related capability value may be used.

Alternatively, even if the UE does not supportbeamCorrespondenceWithoutUL-BeamSweeping, X=0 dB may be applied as adefault X value for calculating the ED threshold (until a penalty of XdB is explicitly configured by the BS). This is because a specialproblem does not occur even if the ED threshold is not differentlyconfigured depending on whether beamCorrespondenceWithoutUL-BeamSweepingis supported according to the number of beams and the number of UEsoperated in a cell.

The various descriptions, functions, procedures, proposals, methods,and/or operation flowcharts of the present disclosure described hereinmay be applied to, but not limited to, various fields requiring wirelesscommunication/connectivity (e.g., 5G) between devices.

More specific examples will be described below with reference to thedrawings. In the following drawings/description, like reference numeralsdenote the same or corresponding hardware blocks, software blocks, orfunction blocks, unless otherwise specified.

FIG. 26 illustrates a communication system 1 applied to the presentdisclosure.

Referring to FIG. 26 , the communication system 1 applied to the presentdisclosure includes wireless devices, BSs, and a network. A wirelessdevice is a device performing communication using radio accesstechnology (RAT) (e.g., 5G NR (or New RAT) or LTE), also referred to asa communication/radio/5G device. The wireless devices may include, notlimited to, a robot 100 a, vehicles 100 b-1 and 100 b-2, an extendedreality (XR) device 100 c, a hand-held device 100 d, a home appliance100 e, an IoT device 100 f, and an artificial intelligence (AI)device/server 400. For example, the vehicles may include a vehiclehaving a wireless communication function, an autonomous driving vehicle,and a vehicle capable of vehicle-to-vehicle (V2V) communication. Herein,the vehicles may include an unmanned aerial vehicle (UAV) (e.g., adrone). The XR device may include an augmented reality (AR)/virtualreality (VR)/mixed reality (MR) device and may be implemented in theform of a head-mounted device (HMD), a head-up display (HUD) mounted ina vehicle, a television (TV), a smartphone, a computer, a wearabledevice, a home appliance, a digital signage, a vehicle, a robot, and soon. The hand-held device may include a smartphone, a smartpad, awearable device (e.g., a smartwatch or smartglasses), and a computer(e.g., a laptop). The home appliance may include a TV, a refrigerator, awashing machine, and so on. The IoT device may include a sensor, asmartmeter, and so on. For example, the BSs and the network may beimplemented as wireless devices, and a specific wireless device 200 amay operate as a BS/network node for other wireless devices.

The wireless devices 100 a to 100 f may be connected to the network 300via the BSs 200. An AI technology may be applied to the wireless devices100 a to 100 f, and the wireless devices 100 a to 100 f may be connectedto the AI server 400 via the network 300. The network 300 may beconfigured using a 3G network, a 4G (e.g., LTE) network, or a 5G (e.g.,NR) network. Although the wireless devices 100 a to 100 f maycommunicate with each other through the BSs 200/network 300, thewireless devices 100 a to 100 f may perform direct communication (e.g.,sidelink communication) with each other without intervention of theBSs/network. For example, the vehicles 100 b-1 and 100 b-2 may performdirect communication (e.g. V2V/vehicle-to-everything (V2X)communication). The IoT device (e.g., a sensor) may perform directcommunication with other IoT devices (e.g., sensors) or other wirelessdevices 100 a to 100 f.

Wireless communication/connections 150 a, 150 b, and 150 c may beestablished between the wireless devices 100 a to 100 f/BS 200 andbetween the BSs 200. Herein, the wireless communication/connections maybe established through various RATs (e.g., 5G NR) such as UL/DLcommunication 150 a, sidelink communication 150 b (or, D2Dcommunication), or inter-BS communication (e.g. relay or integratedaccess backhaul (IAB)). Wireless signals may be transmitted and receivedbetween the wireless devices, between the wireless devices and the BSs,and between the BSs through the wireless communication/connections 150a, 150 b, and 150 c. For example, signals may be transmitted and receivedon various physical channels through the wirelesscommunication/connections 150 a, 150 b and 150 c. To this end, at leasta part of various configuration information configuring processes,various signal processing processes (e.g., channel encoding/decoding,modulation/demodulation, and resource mapping/demapping), and resourceallocation processes, for transmitting/receiving wireless signals, maybe performed based on the various proposals of the present disclosure.

FIG. 27 illustrates wireless devices applicable to the presentdisclosure.

Referring to FIG. 27 , a first wireless device 100 and a second wirelessdevice 200 may transmit wireless signals through a variety of RATs(e.g., LTE and NR). {The first wireless device 100 and the secondwireless device 200} may correspond to {the wireless device 100 x andthe BS 200} and/or {the wireless device 100 x and the wireless device100 x} of FIG. 26 .

The first wireless device 100 may include one or more processors 102 andone or more memories 104, and further include one or more transceivers106 and/or one or more antennas 108. The processor(s) 102 may controlthe memory(s) 104 and/or the transceiver(s) 106 and may be configured toimplement the descriptions, functions, procedures, proposals, methods,and/or operation flowcharts disclosed in this document. For example, theprocessor(s) 102 may process information in the memory(s) 104 togenerate first information/signals and then transmit wireless signalsincluding the first information/signals through the transceiver(s) 106.The processor(s) 102 may receive wireless signals including secondinformation/signals through the transceiver(s) 106 and then storeinformation obtained by processing the second information/signals in thememory(s) 104. The memory(s) 104 may be connected to the processor(s)102 and may store various pieces of information related to operations ofthe processor(s) 102. For example, the memory(s) 104 may store softwarecode including instructions for performing all or a part of processescontrolled by the processor(s) 102 or for performing the descriptions,functions, procedures, proposals, methods, and/or operation flowchartsdisclosed in this document. The processor(s) 102 and the memory(s) 104may be a part of a communication modem/circuit/chip designed toimplement RAT (e.g., LTE or NR). The transceiver(s) 106 may be connectedto the processor(s) 102 and transmit and/or receive wireless signalsthrough the one or more antennas 108. Each of the transceiver(s) 106 mayinclude a transmitter and/or a receiver. The transceiver(s) 106 may beinterchangeably used with radio frequency (RF) unit(s). In the presentdisclosure, the wireless device may be a communicationmodem/circuit/chip.

Specifically, instructions and/or operations, controlled by theprocessor 102 of the first wireless device 100 and stored in the memory104 of the first wireless device 100, according to an embodiment of thepresent disclosure will be described.

Although the following operations will be described based on a controloperation of the processor 102 in terms of the processor 102, softwarecode for performing such an operation may be stored in the memory 104.For example, in the present disclosure, the at least one memory 104 maybe a computer-readable storage medium and may store instructions orprograms. The instructions or programs may cause, when executed, the atleast one processor operably connected to the at least one memory toperform operations according to embodiments or implementations of thepresent disclosure, related to the following operations.

Specifically, the processor 102 may obtain an ED threshold for energysensing. For example, the processor 102 may obtain the ED thresholdbased on at least one of [Proposed Method #1], [Proposed Method #2], or[Proposed Method #4]. However, the processor may also obtain the EDthreshold by the prior art and methods other than the proposed methodsaccording to the present disclosure.

The processor 102 may obtain an LBT-BW. For example, the processor 102may obtain the LBT-BW based on [Proposed Method #3]. However, a methodof obtaining the LBT-BW according to [Proposed Method #3] may beomitted. If the method of obtaining the LBT-BW according to [ProposedMethod #3] is omitted, the processor 102 may perform LBT based on anLBT-BW (e.g., 20 MHz) according to the prior art or perform LBT using aconfigured BWP size as an LBT-BW unit.

The processor 102 may perform LBT based on the obtained ED thresholdand/or LBT-BW. In addition, upon succeeding in LBT, the processor 102may control the transceiver 106 to transmit a UL signal to the BS. Forexample, the processor 102 may perform LBT based on [Proposed Method #2]for multiplexed Tx beams and control the transceiver 106 to transmit theUL signal.

The processor 102 may control the transceiver 106 to receive a DL signalfrom the BS.

The second wireless device 200 may include one or more processors 202and one or more memories 204, and further include one or moretransceivers 206 and/or one or more antennas 208. The processor(s) 202may control the memory(s) 204 and/or the transceiver(s) 206 and may beconfigured to implement the descriptions, functions, procedures,proposals, methods, and/or operation flowcharts disclosed in thisdocument. For example, the processor(s) 202 may process information inthe memory(s) 204 to generate third information/signals and thentransmit wireless signals including the third information/signalsthrough the transceiver(s) 206. The processor(s) 202 may receivewireless signals including fourth information/signals through thetransceiver(s) 106 and then store information obtained by processing thefourth information/signals in the memory(s) 204. The memory(s) 204 maybe connected to the processor(s) 202 and store various pieces ofinformation related to operations of the processor(s) 202. For example,the memory(s) 204 may store software code including instructions forperforming all or a part of processes controlled by the processor(s) 202or for performing the descriptions, functions, procedures, proposals,methods, and/or operation flowcharts disclosed in this document. Theprocessor(s) 202 and the memory(s) 204 may be a part of a communicationmodem/circuit/chip designed to implement RAT (e.g., LTE or NR). Thetransceiver(s) 206 may be connected to the processor(s) 202 and transmitand/or receive wireless signals through the one or more antennas 208.Each of the transceiver(s) 206 may include a transmitter and/or areceiver. The transceiver(s) 206 may be interchangeably used with RFunit(s). In the present disclosure, the wireless device may be acommunication modem/circuit/chip.

Specifically, instructions and/or operations, controlled by theprocessor 202 of the second wireless device 100 and stored in the memory204 of the second wireless device 200, according to an embodiment of thepresent disclosure will be described.

Although the following operations will be described based on a controloperation of the processor 202 in terms of the processor 202, softwarecode for performing such an operation may be stored in the memory 204.For example, in the present disclosure, the at least one memory 204 maybe a computer-readable storage medium and may store instructions orprograms. The instructions or programs may cause, when executed, the atleast one processor operably connected to the at least one memory toperform operations according to embodiments or implementations of thepresent disclosure, related to the following operations.

Specifically, the processor 202 may obtain an ED threshold for energysensing. For example, the processor 202 may acquire the ED thresholdbased on at least one of [Proposed Method #1], [Proposed Method #2], or[Proposed Method #4]. However, the processor 202 may also obtain the EDthreshold by the prior art and methods other than the proposed methodsaccording to the present disclosure.

The processor 202 may configure an LBT-BW. For example, the processor202 may configure the LBT-BW based on [Proposed Method #3]. However, amethod of configuring the LBT-BW according to [Proposed Method #3] maybe omitted. If the method of configuring the LBT-BW according to[Proposed Method #3] is omitted, the processor 202 may perform LBT basedon an LBT-BW (e.g., 20 MHz) according to the prior art or perform LBTusing a configured BWP size as an LBT-BW unit.

The processor 202 may perform LBT based on the obtained ED thresholdand/or LBT-BW (S2205). Upon succeeding LBT, the processor 202 maycontrol the transceiver 206 to transmit a DL signal to the UE. Forexample, the processor 202 may perform LBT for multiplexed Tx beamsbased on [Proposed Method #2] and control the transceiver 206 totransmit the DL signal.

The processor 202 may control the transceiver 206 to receive a UL signalfrom the UE.

Now, hardware elements of the wireless devices 100 and 200 will bedescribed in greater detail. One or more protocol layers may beimplemented by, not limited to, one or more processors 102 and 202. Forexample, the one or more processors 102 and 202 may implement one ormore layers (e.g., functional layers such as physical (PHY), mediumaccess control (MAC), radio link control (RLC), packet data convergenceprotocol (PDCP), RRC, and service data adaptation protocol (SDAP)). Theone or more processors 102 and 202 may generate one or more protocoldata units (PDUs) and/or one or more service data Units (SDUs) accordingto the descriptions, functions, procedures, proposals, methods, and/oroperation flowcharts disclosed in this document. The one or moreprocessors 102 and 202 may generate messages, control information, data,or information according to the descriptions, functions, procedures,proposals, methods, and/or operation flowcharts disclosed in thisdocument and provide the messages, control information, data, orinformation to one or more transceivers 106 and 206. The one or moreprocessors 102 and 202 may generate signals (e.g., baseband signals)including PDUs, SDUs, messages, control information, data, orinformation according to the descriptions, functions, procedures,proposals, methods, and/or operation flowcharts disclosed in thisdocument and provide the generated signals to the one or moretransceivers 106 and 206. The one or more processors 102 and 202 mayreceive the signals (e.g., baseband signals) from the one or moretransceivers 106 and 206 and acquire the PDUs, SDUs, messages, controlinformation, data, or information according to the descriptions,functions, procedures, proposals, methods, and/or operation flowchartsdisclosed in this document.

The one or more processors 102 and 202 may be referred to ascontrollers, microcontrollers, microprocessors, or microcomputers. Theone or more processors 102 and 202 may be implemented by hardware,firmware, software, or a combination thereof. For example, one or moreapplication specific integrated circuits (ASICs), one or more digitalsignal processors (DSPs), one or more digital signal processing devices(DSPDs), one or more programmable logic devices (PLDs), or one or morefield programmable gate arrays (FPGAs) may be included in the one ormore processors 102 and 202. The descriptions, functions, procedures,proposals, methods, and/or operation flowcharts disclosed in thisdocument may be implemented using firmware or software, and the firmwareor software may be configured to include the modules, procedures, orfunctions. Firmware or software configured to perform the descriptions,functions, procedures, proposals, methods, and/or operation flowchartsdisclosed in this document may be included in the one or more processors102 and 202 or may be stored in the one or more memories 104 and 204 andexecuted by the one or more processors 102 and 202. The descriptions,functions, procedures, proposals, methods, and/or operation flowchartsdisclosed in this document may be implemented using firmware or softwarein the form of code, an instruction, and/or a set of instructions.

The one or more memories 104 and 204 may be connected to the one or moreprocessors 102 and 202 and store various types of data, signals,messages, information, programs, code, instructions, and/or commands.The one or more memories 104 and 204 may be configured to includeread-only memories (ROMs), random access memories (RAMs), electricallyerasable programmable read-only memories (EPROMs), flash memories, harddrives, registers, cash memories, computer-readable storage media,and/or combinations thereof. The one or more memories 104 and 204 may belocated at the interior and/or exterior of the one or more processors102 and 202. The one or more memories 104 and 204 may be connected tothe one or more processors 102 and 202 through various technologies suchas wired or wireless connection.

The one or more transceivers 106 and 206 may transmit user data, controlinformation, and/or wireless signals/channels, mentioned in the methodsand/or operation flowcharts of this document, to one or more otherdevices. The one or more transceivers 106 and 206 may receive user data,control information, and/or wireless signals/channels, mentioned in thedescriptions, functions, procedures, proposals, methods, and/oroperation flowcharts disclosed in this document, from one or more otherdevices. For example, the one or more transceivers 106 and 206 may beconnected to the one or more processors 102 and 202 and transmit andreceive wireless signals. For example, the one or more processors 102and 202 may perform control so that the one or more transceivers 106 and206 may transmit user data, control information, or wireless signals toone or more other devices. The one or more processors 102 and 202 mayperform control so that the one or more transceivers 106 and 206 mayreceive user data, control information, or wireless signals from one ormore other devices. The one or more transceivers 106 and 206 may beconnected to the one or more antennas 108 and 208 and the one or moretransceivers 106 and 206 may be configured to transmit and receive userdata, control information, and/or wireless signals/channels, mentionedin the descriptions, functions, procedures, proposals, methods, and/oroperation flowcharts disclosed in this document, through the one or moreantennas 108 and 208. In this document, the one or more antennas may bea plurality of physical antennas or a plurality of logical antennas(e.g., antenna ports). The one or more transceivers 106 and 206 mayconvert received wireless signals/channels from RF band signals intobaseband signals in order to process received user data, controlinformation, and wireless signals/channels using the one or moreprocessors 102 and 202. The one or more transceivers 106 and 206 mayconvert the user data, control information, and wirelesssignals/channels processed using the one or more processors 102 and 202from the baseband signals into the RF band signals. To this end, the oneor more transceivers 106 and 206 may include (analog) oscillators and/orfilters.

FIG. 28 illustrates a vehicle or an autonomous driving vehicle appliedto the present disclosure. The vehicle or autonomous driving vehicle maybe implemented as a mobile robot, a car, a train, a manned/unmannedaerial vehicle (AV), a ship, or the like.

Referring to FIG. 28 , a vehicle or autonomous driving vehicle 100 mayinclude an antenna unit 108, a communication unit 110, a control unit120, a driving unit 140 a, a power supply unit 140 b, a sensor unit 140c, and an autonomous driving unit 140 d. The antenna unit 108 may beconfigured as a part of the communication unit 110.

The communication unit 110 may transmit and receive signals (e.g., dataand control signals) to and from external devices such as othervehicles, BSs (e.g., gNBs and road side units), and servers. The controlunit 120 may perform various operations by controlling elements of thevehicle or the autonomous driving vehicle 100. The control unit 120 mayinclude an ECU. The driving unit 140 a may enable the vehicle or theautonomous driving vehicle 100 to drive on a road. The driving unit 140a may include an engine, a motor, a powertrain, a wheel, a brake, asteering device, and so on. The power supply unit 140 b may supply powerto the vehicle or the autonomous driving vehicle 100 and include awired/wireless charging circuit, a battery, and so on. The sensor unit140 c may acquire information about a vehicle state, ambient environmentinformation, user information, and so on. The sensor unit 140 c mayinclude an inertial measurement unit (IMU) sensor, a collision sensor, awheel sensor, a speed sensor, a slope sensor, a weight sensor, a headingsensor, a position module, a vehicle forward/backward sensor, a batterysensor, a fuel sensor, a tire sensor, a steering sensor, a temperaturesensor, a humidity sensor, an ultrasonic sensor, an illumination sensor,a pedal position sensor, and so on. The autonomous driving unit 140 dmay implement technology for maintaining a lane on which the vehicle isdriving, technology for automatically adjusting speed, such as adaptivecruise control, technology for autonomously driving along a determinedpath, technology for driving by automatically setting a route if adestination is set, and the like.

For example, the communication unit 110 may receive map data, trafficinformation data, and so on from an external server. The autonomousdriving unit 140 d may generate an autonomous driving route and adriving plan from the obtained data. The control unit 120 may controlthe driving unit 140 a such that the vehicle or autonomous drivingvehicle 100 may move along the autonomous driving route according to thedriving plan (e.g., speed/direction control). During autonomous driving,the communication unit 110 may aperiodically/periodically acquire recenttraffic information data from the external server and acquiresurrounding traffic information data from neighboring vehicles. Duringautonomous driving, the sensor unit 140 c may obtain information about avehicle state and/or surrounding environment information. The autonomousdriving unit 140 d may update the autonomous driving route and thedriving plan based on the newly obtained data/information. Thecommunication unit 110 may transfer information about a vehicleposition, the autonomous driving route, and/or the driving plan to theexternal server. The external server may predict traffic informationdata using AI technology based on the information collected fromvehicles or autonomous driving vehicles and provide the predictedtraffic information data to the vehicles or the autonomous drivingvehicles.

The embodiments of the present disclosure described herein below arecombinations of elements and features of the present disclosure. Theelements or features may be considered selective unless otherwisementioned. Each element or feature may be practiced without beingcombined with other elements or features. Further, an embodiment of thepresent disclosure may be constructed by combining parts of the elementsand/or features. Operation orders described in embodiments of thepresent disclosure may be rearranged. Some constructions of any oneembodiment may be included in another embodiment and may be replacedwith corresponding constructions of another embodiment. It will beobvious to those skilled in the art that claims that are not explicitlycited in each other in the appended claims may be presented incombination as an embodiment of the present disclosure or included as anew claim by a subsequent amendment after the application is filed.

In the present disclosure, a specific operation described as performedby the BS may be performed by an upper node of the BS in some cases.Namely, it is apparent that, in a network comprised of a plurality ofnetwork nodes including a BS, various operations performed forcommunication with an MS may be performed by the BS, or network nodesother than the BS. The term ‘BS’ may be replaced with the term ‘fixedstation’, ‘Node B’, ‘enhanced Node B (eNode B or eNB)’, ‘access point’,etc.

Those skilled in the art will appreciate that the present disclosure maybe carried out in other specific ways than those set forth hereinwithout departing from the spirit and essential characteristics of thepresent disclosure. The above embodiments are therefore to be construedin all aspects as illustrative and not restrictive. The scope of thedisclosure should be determined by the appended claims and their legalequivalents, not by the above description, and all changes coming withinthe meaning and equivalency range of the appended claims are intended tobe embraced therein.

While the above-described method of performing a CAP and the apparatustherefor have been described based on an example applied to a 5G NRsystem, the method and apparatus are applicable to various wirelesscommunication systems in addition to the 5G NR system.

1. A method of transmitting an uplink signal by a user equipment (UE) ina wireless communication system, the method comprising: performinglisten-before-talk (LBT) based on at least one LBT beam; andtransmitting the uplink signal through a plurality of transmission beamsbased on success of the LBT, wherein the at least one LBT beam coversthe plurality of transmission beams, and the plurality of transmissionbeams is multiplexed.
 2. The method of claim 1, wherein the plurality oftransmission beams is multiplexed using spatial division multiplexing(SDM).
 3. The method of claim 1, wherein the plurality of transmissionbeams is multiplexed using time division multiplexing (TDM).
 4. Themethod of claim 1, wherein the at least one LBT beam is a single LBTbeam covering all of the plurality of transmission beams.
 5. The methodof claim 1, wherein the at least one LBT beam includes a plurality ofLBT beams, and each of the plurality of LBT beams covers each of theplurality of transmission beams.
 6. The method of claim 1, whereinCategory 2 (Cat-2) LBT is performed before beam switching is performedbetween the plurality of transmission beams.
 7. A user equipment (UE)for transmitting an uplink signal in a wireless communication system,the UE comprising: at least one transceiver; at least one processor; andat least one memory operably connected to the at least one processor andconfigured to store instructions that, when executed, cause the at leastone processor to perform operations comprising: performinglisten-before-talk (LBT) based on at least one LBT beam; andtransmitting, through the at least one transceiver, the uplink signalthrough a plurality of transmission beams based on success of the LBT,and wherein the at least one LBT beam covers the plurality oftransmission beams, and the plurality of transmission beams ismultiplexed.
 8. The UE of claim 7, wherein the plurality of transmissionbeams is multiplexed using spatial division multiplexing (SDM).
 9. TheUE of claim 7, wherein the plurality of transmission beams ismultiplexed using time division multiplexing (TDM).
 10. The UE of claim7, wherein the at least one LBT beam is a single LBT beam covering allof the plurality of transmission beams.
 11. The UE of claim 7, whereinthe at least one LBT beam includes a plurality of LBT beams, and each ofthe plurality of LBT beams covers each of the plurality of transmissionbeams.
 12. The UE of claim 11, wherein Category 2 (Cat-2) LBT isperformed before beam switching is performed between the plurality oftransmission beams. 13-14. (canceled)
 15. A method of transmitting adownlink signal by a base station in a wireless communication system,the method comprising: performing listen-before-talk (LBT) based on atleast one LBT beam; and transmitting the downlink signal through aplurality of transmission beams based on success of the LBT, wherein theat least one LBT beam covers the plurality of transmission beams, andthe plurality of transmission beams is multiplexed.
 16. (canceled)
 17. Anon-transitory medium which is readable by a processor and storinginstructions cause the processor to perform the method of claim 1.